Graphing worksheet with four real-world scenarios represented by line graphs, asking students to find slope, y-intercept, and write equations.
Graphing worksheet with four line graphs showing relationships between variables like cost, number of passes, pizzas, servings, and minutes, each with labeled axes and questions about slope, y-intercept, and equation.
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Step-by-step solution for: Interpreting-slope-and-y-intercept-worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Interpreting-slope-and-y-intercept-worksheet
Absolutely! Let’s go through each graph one by one, find the slope and y-intercept, interpret them in real-world context, and write the equation in the form y = mx + b.
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- x-axis: Number of passes
- y-axis: Cost (dollars)
#### Step 1: Find two points on the line
Look at the graph:
- When x = 0, y = 6 → Point (0, 6)
- When x = 2, y = 12 → Point (2, 12)
#### Step 2: Calculate slope (m)
Slope = rise / run = (change in y) / (change in x)
→ m = (12 - 6) / (2 - 0) = 6 / 2 = 3
#### Step 3: y-intercept (b)
When x = 0, y = 6 → b = 6
#### Step 4: Real-world interpretation
- Slope = 3: Each additional pool pass costs $3.
- y-intercept = 6: There is a base fee of $6 even if you buy 0 passes (maybe a membership or activation fee).
#### Step 5: Equation
Let y = cost (dollars), x = number of passes
→ y = 3x + 6
---
- x-axis: Number of people
- y-axis: Number of pizzas
#### Step 1: Pick two points
- (0, 0) — 0 people → 0 pizzas
- (10, 6) — 10 people → 6 pizzas
#### Step 2: Slope
m = (6 - 0) / (10 - 0) = 6/10 = 0.6
#### Step 3: y-intercept
At x=0, y=0 → b = 0
#### Step 4: Real-world interpretation
- Slope = 0.6: For every 1 person, you need 0.6 of a pizza (or 3/5 of a pizza). So, for every 5 people, you need 3 pizzas.
- y-intercept = 0: If there are 0 people, you order 0 pizzas — makes sense!
#### Step 5: Equation
Let y = number of pizzas, x = number of people
→ y = 0.6x
*(You could also write it as y = (3/5)x if fractions are preferred)*
---
- x-axis: Number of servings
- y-axis: Cost (dollars)
#### Step 1: Pick two points
- (0, 0) — 0 servings → $0
- (80, 120) — 80 servings → $120? Wait — let’s check the scale.
Actually, looking closely:
- At x = 80, y = 120? But the grid goes up to 100, and the line ends at about y=120? Wait — let me recheck.
Looking again — the y-axis goes up to 100 in increments of 20. The line ends at (80, 120)? That doesn’t match the grid.
Wait — actually, the top of the graph says “Cost (dollars)” and the highest mark is 100. The line ends at x=80, y=100? Let’s confirm:
At x=0, y=0
At x=80, y=100 → that fits the grid.
So point (80, 100)
#### Step 2: Slope
m = (100 - 0) / (80 - 0) = 100/80 = 1.25
#### Step 3: y-intercept
(0,0) → b = 0
#### Step 4: Real-world interpretation
- Slope = 1.25: Each serving costs $1.25.
- y-intercept = 0: No servings means no cost — makes sense.
#### Step 5: Equation
Let y = cost (dollars), x = number of servings
→ y = 1.25x
*(Or y = (5/4)x)*
---
- x-axis: Days of month
- y-axis: Number of minutes
This line is decreasing — so slope will be negative.
#### Step 1: Pick two points
- (0, 60) — Day 0 → 60 minutes left
- (24, 0) — Day 24 → 0 minutes left
#### Step 2: Slope
m = (0 - 60) / (24 - 0) = (-60)/24 = -2.5
#### Step 3: y-intercept
At x=0, y=60 → b = 60
#### Step 4: Real-world interpretation
- Slope = -2.5: You use 2.5 minutes per day. (The negative sign means minutes are decreasing over time.)
- y-intercept = 60: On day 0 (start of the month), you have 60 minutes available.
#### Step 5: Equation
Let y = number of minutes remaining, x = days of month
→ y = -2.5x + 60
*(Or y = -(5/2)x + 60)*
---
## ✔ Final Answers:
---
- Slope = 3
- y-intercept = 6
- Real-world interpretation of slope: Each additional pool pass costs $3.
- Equation: y = 3x + 6
---
- Slope = 0.6
- y-intercept = 0
- Real-world interpretation of slope: For every person, you need 0.6 of a pizza (or 3 pizzas for every 5 people).
- Equation: y = 0.6x
---
- Slope = 1.25
- y-intercept = 0
- Real-world interpretation of slope: Each serving costs $1.25.
- Equation: y = 1.25x
---
- Slope = -2.5
- y-intercept = 60
- Real-world interpretation of slope: You use 2.5 minutes per day.
- Equation: y = -2.5x + 60
---
Let me know if you’d like these equations rewritten with fractions or in different forms!
---
Graph 1: Pool Passes
- x-axis: Number of passes
- y-axis: Cost (dollars)
#### Step 1: Find two points on the line
Look at the graph:
- When x = 0, y = 6 → Point (0, 6)
- When x = 2, y = 12 → Point (2, 12)
#### Step 2: Calculate slope (m)
Slope = rise / run = (change in y) / (change in x)
→ m = (12 - 6) / (2 - 0) = 6 / 2 = 3
#### Step 3: y-intercept (b)
When x = 0, y = 6 → b = 6
#### Step 4: Real-world interpretation
- Slope = 3: Each additional pool pass costs $3.
- y-intercept = 6: There is a base fee of $6 even if you buy 0 passes (maybe a membership or activation fee).
#### Step 5: Equation
Let y = cost (dollars), x = number of passes
→ y = 3x + 6
---
Graph 2: Number of Pizzas to Order
- x-axis: Number of people
- y-axis: Number of pizzas
#### Step 1: Pick two points
- (0, 0) — 0 people → 0 pizzas
- (10, 6) — 10 people → 6 pizzas
#### Step 2: Slope
m = (6 - 0) / (10 - 0) = 6/10 = 0.6
#### Step 3: y-intercept
At x=0, y=0 → b = 0
#### Step 4: Real-world interpretation
- Slope = 0.6: For every 1 person, you need 0.6 of a pizza (or 3/5 of a pizza). So, for every 5 people, you need 3 pizzas.
- y-intercept = 0: If there are 0 people, you order 0 pizzas — makes sense!
#### Step 5: Equation
Let y = number of pizzas, x = number of people
→ y = 0.6x
*(You could also write it as y = (3/5)x if fractions are preferred)*
---
Graph 3: Cost of Birthday Cake
- x-axis: Number of servings
- y-axis: Cost (dollars)
#### Step 1: Pick two points
- (0, 0) — 0 servings → $0
- (80, 120) — 80 servings → $120? Wait — let’s check the scale.
Actually, looking closely:
- At x = 80, y = 120? But the grid goes up to 100, and the line ends at about y=120? Wait — let me recheck.
Looking again — the y-axis goes up to 100 in increments of 20. The line ends at (80, 120)? That doesn’t match the grid.
Wait — actually, the top of the graph says “Cost (dollars)” and the highest mark is 100. The line ends at x=80, y=100? Let’s confirm:
At x=0, y=0
At x=80, y=100 → that fits the grid.
So point (80, 100)
#### Step 2: Slope
m = (100 - 0) / (80 - 0) = 100/80 = 1.25
#### Step 3: y-intercept
(0,0) → b = 0
#### Step 4: Real-world interpretation
- Slope = 1.25: Each serving costs $1.25.
- y-intercept = 0: No servings means no cost — makes sense.
#### Step 5: Equation
Let y = cost (dollars), x = number of servings
→ y = 1.25x
*(Or y = (5/4)x)*
---
Graph 4: Cellular Phone Plan
- x-axis: Days of month
- y-axis: Number of minutes
This line is decreasing — so slope will be negative.
#### Step 1: Pick two points
- (0, 60) — Day 0 → 60 minutes left
- (24, 0) — Day 24 → 0 minutes left
#### Step 2: Slope
m = (0 - 60) / (24 - 0) = (-60)/24 = -2.5
#### Step 3: y-intercept
At x=0, y=60 → b = 60
#### Step 4: Real-world interpretation
- Slope = -2.5: You use 2.5 minutes per day. (The negative sign means minutes are decreasing over time.)
- y-intercept = 60: On day 0 (start of the month), you have 60 minutes available.
#### Step 5: Equation
Let y = number of minutes remaining, x = days of month
→ y = -2.5x + 60
*(Or y = -(5/2)x + 60)*
---
## ✔ Final Answers:
---
1. Pool Passes
- Slope = 3
- y-intercept = 6
- Real-world interpretation of slope: Each additional pool pass costs $3.
- Equation: y = 3x + 6
---
2. Number of Pizzas to Order
- Slope = 0.6
- y-intercept = 0
- Real-world interpretation of slope: For every person, you need 0.6 of a pizza (or 3 pizzas for every 5 people).
- Equation: y = 0.6x
---
3. Cost of Birthday Cake
- Slope = 1.25
- y-intercept = 0
- Real-world interpretation of slope: Each serving costs $1.25.
- Equation: y = 1.25x
---
4. Cellular Phone Plan
- Slope = -2.5
- y-intercept = 60
- Real-world interpretation of slope: You use 2.5 minutes per day.
- Equation: y = -2.5x + 60
---
Let me know if you’d like these equations rewritten with fractions or in different forms!
Parent Tip: Review the logic above to help your child master the concept of interpreting slope and y intercept worksheet.