Question

15. One of the angles of a triangle is equal to the sum of the other two angles. If the ratio of the other two angis
is 4: 5. find the angles of the triangle.
Find their​

Answer 1

Explanation:

let the first angle be 4x, second angle be 5x.

Then, 3rd angle = 4x + 5x = 9x

A/q

4x+5x+9x = 180° [ angle sum prop. of ∆]

⇒18x = 180°

⇒x = $\frac{180°}{18}$

⇒x = 10°

so, 1st angle = 4×10°= 40°

2nd angle = 5×10° = 50°

3rd angle = 9×10° = 90°