Question

"Question 7 In a right triangle ABC,∠B = 90°. (a) If AB = 6 cm, BC = 8 cm, find AC (b) If AC = 13 cm, BC = 5 cm, find AB

Class 8 Squares and Square Roots Page 107"

Answer 1

Pythagoras Theorem:

In a right-angled triangle, The sum of squares of the lengths of the two sides( base & perpendicular) is equal to the square of the length of the hypotenuse .

 Hypotenuse is  the longest side.

P is perpendicular, B is base , H is hypotenuse

H² = P² + B²

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 Solution:

[Fig. is in the attachment]

a)

AC²= AB² + BC²                   [by Pythagoras Theorem]

= 6² + 8²

 = 36 + 64

AC²= 100

AC= √100

AC= 10

(b) If AC = 13 cm, BC = 5 cm, find AB

AB²= AC²- BC²                          [by Pythagoras Theorem] 

= 13²- 5²

= 169 – 25

 AB²= 144

AB =√ 144

AB= 12

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Hope this will help you...