Find AB and BC given AC = 62 and equal segments AB and BC.
A line segment AC with point B in between, labeled AB = 3x - 4 and BC = 3x - 4, with AC = 62.
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Step-by-step solution for: Segment Addition Postulate | Algebra and Geometry Help
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Show Answer Key & Explanations
Step-by-step solution for: Segment Addition Postulate | Algebra and Geometry Help
We are given a line segment $ AC $ with point $ B $ lying between $ A $ and $ C $. The segments $ AB $ and $ BC $ are both labeled as $ 3x - 4 $. We're told that the total length $ AC = 62 $, and we are to find:
1. The value of $ x $
2. The lengths of $ AB $ and $ BC $
---
From the diagram:
- $ AB = 3x - 4 $
- $ BC = 3x - 4 $
- So, $ AC = AB + BC $
Since $ B $ is between $ A $ and $ C $, we can write:
$$
AC = AB + BC
$$
Substitute the expressions:
$$
62 = (3x - 4) + (3x - 4)
$$
---
$$
62 = 3x - 4 + 3x - 4
$$
$$
62 = 6x - 8
$$
Add 8 to both sides:
$$
62 + 8 = 6x
$$
$$
70 = 6x
$$
Divide by 6:
$$
x = \frac{70}{6} = \frac{35}{3} \approx 11.67
$$
Wait — let's double-check this. Is this correct?
But hold on — let’s verify if this makes sense.
Let’s plug $ x = \frac{35}{3} $ back into $ 3x - 4 $:
$$
3x - 4 = 3 \cdot \frac{35}{3} - 4 = 35 - 4 = 31
$$
Then $ AB = 31 $, $ BC = 31 $, so $ AC = 31 + 31 = 62 $ ✔
So it checks out.
But wait — $ x = \frac{35}{3} $ is approximately 11.67, but the problem may expect an integer? Let’s check our algebra again.
Wait — did we make a mistake?
Wait:
$$
62 = 6x - 8
\Rightarrow 6x = 70
\Rightarrow x = \frac{70}{6} = \frac{35}{3}
$$
Yes, that's correct.
But maybe there’s a typo in the problem or diagram?
Wait — perhaps the labels are meant to be equal, but maybe we’re overcomplicating.
Alternatively, could the expression be different? But based on what’s shown:
- $ AB = 3x - 4 $
- $ BC = 3x - 4 $
- So $ AC = 2(3x - 4) = 6x - 8 $
Set equal to 62:
$$
6x - 8 = 62
\Rightarrow 6x = 70
\Rightarrow x = \frac{35}{3}
$$
Now compute $ AB $ and $ BC $:
$$
AB = 3x - 4 = 3 \cdot \frac{35}{3} - 4 = 35 - 4 = 31
$$
Similarly, $ BC = 31 $
So even though $ x $ is a fraction, the segment lengths are integers.
---
- $ x = \frac{35}{3} $
- $ AB = 31 $
- $ BC = 31 $
---
But let’s ask: Is this expected? Maybe the problem intended $ AB = 3x - 4 $, $ BC = 3x - 4 $, which implies symmetry, so $ B $ is the midpoint.
But unless the problem specifies $ x $ must be integer, this is acceptable.
Alternatively, perhaps the diagram has a typo, and the expressions are meant to be different?
But based on what’s given, this is correct.
---
- $ x = \frac{35}{3} $
- $ AB = 31 $
- $ BC = 31 $
---
But let’s recheck:
$ 3x - 4 = 31 $ → $ 3x = 35 $ → $ x = \frac{35}{3} $, yes.
So the answer is consistent.
---
Answer:
- $ x = \boxed{\frac{35}{3}} $
- $ AB = \boxed{31} $
- $ BC = \boxed{31} $
Let me know if you'd like it written as a mixed number or decimal.
1. The value of $ x $
2. The lengths of $ AB $ and $ BC $
---
Step 1: Understand the diagram
From the diagram:
- $ AB = 3x - 4 $
- $ BC = 3x - 4 $
- So, $ AC = AB + BC $
Since $ B $ is between $ A $ and $ C $, we can write:
$$
AC = AB + BC
$$
Substitute the expressions:
$$
62 = (3x - 4) + (3x - 4)
$$
---
Step 2: Solve for $ x $
$$
62 = 3x - 4 + 3x - 4
$$
$$
62 = 6x - 8
$$
Add 8 to both sides:
$$
62 + 8 = 6x
$$
$$
70 = 6x
$$
Divide by 6:
$$
x = \frac{70}{6} = \frac{35}{3} \approx 11.67
$$
Wait — let's double-check this. Is this correct?
But hold on — let’s verify if this makes sense.
Let’s plug $ x = \frac{35}{3} $ back into $ 3x - 4 $:
$$
3x - 4 = 3 \cdot \frac{35}{3} - 4 = 35 - 4 = 31
$$
Then $ AB = 31 $, $ BC = 31 $, so $ AC = 31 + 31 = 62 $ ✔
So it checks out.
But wait — $ x = \frac{35}{3} $ is approximately 11.67, but the problem may expect an integer? Let’s check our algebra again.
Wait — did we make a mistake?
Wait:
$$
62 = 6x - 8
\Rightarrow 6x = 70
\Rightarrow x = \frac{70}{6} = \frac{35}{3}
$$
Yes, that's correct.
But maybe there’s a typo in the problem or diagram?
Wait — perhaps the labels are meant to be equal, but maybe we’re overcomplicating.
Alternatively, could the expression be different? But based on what’s shown:
- $ AB = 3x - 4 $
- $ BC = 3x - 4 $
- So $ AC = 2(3x - 4) = 6x - 8 $
Set equal to 62:
$$
6x - 8 = 62
\Rightarrow 6x = 70
\Rightarrow x = \frac{35}{3}
$$
Now compute $ AB $ and $ BC $:
$$
AB = 3x - 4 = 3 \cdot \frac{35}{3} - 4 = 35 - 4 = 31
$$
Similarly, $ BC = 31 $
So even though $ x $ is a fraction, the segment lengths are integers.
---
Final Answers:
- $ x = \frac{35}{3} $
- $ AB = 31 $
- $ BC = 31 $
---
But let’s ask: Is this expected? Maybe the problem intended $ AB = 3x - 4 $, $ BC = 3x - 4 $, which implies symmetry, so $ B $ is the midpoint.
But unless the problem specifies $ x $ must be integer, this is acceptable.
Alternatively, perhaps the diagram has a typo, and the expressions are meant to be different?
But based on what’s given, this is correct.
---
✔ Final Answer:
- $ x = \frac{35}{3} $
- $ AB = 31 $
- $ BC = 31 $
---
But let’s recheck:
$ 3x - 4 = 31 $ → $ 3x = 35 $ → $ x = \frac{35}{3} $, yes.
So the answer is consistent.
---
Answer:
- $ x = \boxed{\frac{35}{3}} $
- $ AB = \boxed{31} $
- $ BC = \boxed{31} $
Let me know if you'd like it written as a mixed number or decimal.
Parent Tip: Review the logic above to help your child master the concept of segment addition postulate worksheet.