Let's solve each problem on the
Special Right Triangle - 45°-45°-90° Worksheet step by step.
---
🔷 Key Concept: 45°-45°-90° Triangle
In a
45°-45°-90° triangle:
- The two legs are
equal.
- The hypotenuse is $ \text{leg} \times \sqrt{2} $
- So:
- If leg = $ x $, then hypotenuse = $ x\sqrt{2} $
- If hypotenuse = $ h $, then leg = $ \frac{h}{\sqrt{2}} = \frac{h\sqrt{2}}{2} $
We’ll use this to solve for $ x $ in each triangle.
---
🔹 Problem 1
```
x
/|
/ |
/__|
8
```
- This is a 45°-45°-90° triangle with one leg = 8.
- Since both legs are equal, the other leg is also 8.
- Hypotenuse $ x = 8\sqrt{2} $
✔ Answer: $ x = 8\sqrt{2} $
---
🔹 Problem 2
```
x
/|
/ |
/__|
16
```
- Right angle at bottom right, 45° at top left → this is a 45°-45°-90° triangle.
- One leg is 16, so the other leg (x) is also 16.
- But wait — the side labeled "x" is the
hypotenuse, since it’s opposite the right angle.
Wait! Let's clarify:
- The side labeled
16 is
one leg.
- The side labeled
x is the
hypotenuse.
So:
- Leg = 16
- Hypotenuse = $ 16\sqrt{2} $
✔ Answer: $ x = 16\sqrt{2} $
---
🔹 Problem 3
```
12
/|
/ |
/__|
x
```
- Right angle at bottom right, 45° at top → this is a 45°-45°-90° triangle.
- The side of length 12 is the
hypotenuse.
- We need to find a leg: $ x = \frac{12}{\sqrt{2}} = \frac{12\sqrt{2}}{2} = 6\sqrt{2} $
✔ Answer: $ x = 6\sqrt{2} $
---
🔹 Problem 4
```
24
/|
/ |
/__|
x x
```
- Right triangle with two legs labeled $ x $, and hypotenuse = 24.
- So: $ x\sqrt{2} = 24 $
- $ x = \frac{24}{\sqrt{2}} = \frac{24\sqrt{2}}{2} = 12\sqrt{2} $
✔ Answer: $ x = 12\sqrt{2} $
---
🔹 Problem 5
```
x
/|
/ |
/__|
3√2
```
- Right angle at bottom right, 45° at top → 45°-45°-90° triangle.
- One leg = $ 3\sqrt{2} $
- Since both legs are equal, $ x = 3\sqrt{2} $
- Wait — is $ x $ the leg or the hypotenuse?
Looking at the diagram:
- The side labeled $ x $ is
one leg.
- The other leg is $ 3\sqrt{2} $
- Since both legs are equal, $ x = 3\sqrt{2} $
✔ Answer: $ x = 3\sqrt{2} $
---
🔹 Problem 6
```
x
/|
/ |
/__|
18
```
- Right angle at bottom right, 45° at top → 45°-45°-90° triangle.
- The side labeled 18 is
one leg.
- The side labeled $ x $ is the
hypotenuse.
- So: $ x = 18\sqrt{2} $
✔ Answer: $ x = 18\sqrt{2} $
---
🔹 Problem 7
```
22
/|
/ |
/__|
x
```
- Right triangle with 45° angle at top right.
- One leg is $ x $, hypotenuse is 22.
- This is a 45°-45°-90° triangle → both legs are equal.
- So: $ x\sqrt{2} = 22 $
- $ x = \frac{22}{\sqrt{2}} = \frac{22\sqrt{2}}{2} = 11\sqrt{2} $
✔ Answer: $ x = 11\sqrt{2} $
---
🔹 Problem 8
```
+-----+
| | 5
| |
| |
+-----+
x
```
This is a
square with side 5. A diagonal is drawn, labeled $ x $. The diagonal divides the square into two
45°-45°-90° triangles.
- Each leg of the triangle is 5.
- Hypotenuse $ x = 5\sqrt{2} $
✔ Answer: $ x = 5\sqrt{2} $
---
✔ Final Answers:
| Problem | Answer |
|--------|--------------------|
| 1 | $ 8\sqrt{2} $ |
| 2 | $ 16\sqrt{2} $ |
| 3 | $ 6\sqrt{2} $ |
| 4 | $ 12\sqrt{2} $ |
| 5 | $ 3\sqrt{2} $ |
| 6 | $ 18\sqrt{2} $ |
| 7 | $ 11\sqrt{2} $ |
| 8 | $ 5\sqrt{2} $ |
---
Let me know if you'd like these answers boxed or formatted differently!
Parent Tip: Review the logic above to help your child master the concept of is it a right triangle worksheet.