Question

EXERCISE 15D
1. Find the length of the hypotenuse of a right triangle, the other two sides of which measure
9 cm and 12 cm.
2. The hypotenuse of a right triangle is 26 cm long. If one of the remaining two sides is 10 cm
long, find the length of the other side.
3. The length of one side of a right triangle is 4.5 cm and the length of its hypotenuse is 7.5 cm.
Find the length of its third side.
Hint. Let the third side be x cm. Then,
x2 = (7.5)2 – (4.5)2 = (7.5 +4.5)(7.5-4.5)=(12x3) = 36 = (6)2.
​

Answer 1

1)

By Pythagoras Theorem,

AC² = AB² + BC² = (9)² + (12)² = 81 + 144 = 225

AC = √225 = 15 cm

2.)

In right ∆ABC, ∠B = 90°

AC = 26cm, AB = 10cm

By Pythagoras Theorem

AC² = AB² + BC²

RS Aggarwal Class 7 Solutions Chapter 15 Properties of Triangles Ex 15D 2

⇒ (26)² = (10)² + BC²

⇒ 676 = 100 + BC²

⇒ BC² = 676 – 100 = 576 = (24)²

⇒ BC = 24 cm

3.)

In right ∆ABC, ∠C = 90°,

AB = 7.5cm, BC = 4.5cm

By Pythagoras Theorem

AB² = BC² + AC

⇒ (7.5)² = (4.5)² + AC²

⇒ 56.25 = 20.25 + AC²

⇒ AC² = 56.25 – 20.25 = 36.00 = (6)²

⇒ AC = 6cm

plz mark me brainliest

Answer 2

Step-by-step explanation:

ho gya question 1, 2, 3 complete