Question

b) If the sides of a triangle are in the ratio 3:4:5, prove that it is a right-angled triangle.

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Answer 1

Answer:

let sides:-3x;4x;5x

3x+4x+5x=180(angles sum of equilateral triangle)

12x=180

x=180÷12

x=15

sides:-3x=3×15=45

4x=4×15=60

5x=5×15=75

Answer 2

Answer:

let a,b,c a triangle

now according to question

a=3x

b=4x

c=5x

according to pythagorus theoram

ac^2 =bc^2 + ab^2

after solving it we will get

ac^2=(5x)^2 = 25x^2

ac^2 = bc^2 + ab^2

hence abc is right angled triangle