Question

Solve each of the following problems by using two variables.

In ∆ABC, ∠A = xº, ∠B = 3xº and ∠C = yº. If 3y - 5x = 30. Prove that the triangle is right angled.
(linear equation in one variable)(9std)​

Answer 1

Step-by-step explanation:

given = 3y-5x=30

3y =30+5x

y=30+5x÷3

now , in a triangle sum of 3 angles is 180° .

x+3x+ y =180

putting 30+5x÷3 in place of y , we get

x+3x+30+5x÷3=180

4x+30+5x÷3= 180

12x+30+5x÷3=180

12x+30+5x =180×3

17x+30 =540

17x =540-30

x=510÷17

= 30

in triangle ABC ,

x=30

3x=90

y = 60 ( by substituting the value of x in 30+5x÷3)

therefore the triangle is right angled