Solution:
Step-1: Find the missing angle.
- 90 + 45 + y = 180
- => 135 + y = 180
- => y = 180 - 135
- => y = 45°
Step-2: Review the following.
- This triangle is an isosceles right triangle because two angles are equivalent.
- Two sides of the triangle must equal 4 cm.
Step-3: Use Pythagoras theorem.
- x² = 4² + 4²
- => x² = 16 + 16
- => x = √32 ≈ 5.65 cm (Using calculator)