Question

2 angles of a triangle are in ratio 4:5 if they sum to third angle find the angles

Answer 1

Let,
Angles are,
•4x
•5x
•4x+5x=9x

======================


Sum of angles of a triangle = 180

4x +5x +4x +5x = 180

18x =180

x =180/18

x =10

_______________

Angles are

•4x =4×10=40°
•5x =5×10=50°
•40+50=90°


I hope this will help you


-by ABHAY

Answer 2

let ABC be the triangle.
∠A = 4x and ∠B = 5x
∴ ∠C = ∠A +∠B
ie, ∠C = 4x + 5x
           = 9x

by the angle sum property of a triangle,
  ∠A + ∠B + ∠C = 180°
   4x + 5x + 9x = 180°
                 18x = 180°
             x = 180°÷18
             x = 10°

∴ ∠A = 4x = 4(10) = 40°
   ∠B = 5x = 5(10) = 50°
and,∠C = 9x = 9(10) = 90°



Hope this will help...
This is very simple to understand...