Question

the size of the interior angles of a triangle are in the ratio 3:4:5 Find the size of its largest angle.(hint:the sum of the interior angles of a triangle is 180°)

Answer 1

Let the ratio be x.
So the required angles are 3x,4x and 5x.
a/q
3x+4x+5x=180
12x=180
x=15
Therefore size of largest angle=5x=5×15=75°

Answer 2

Ratio = 3 : 4 : 5

Define x:

Let x be the constant ratio

Ratio = 3x : 4x : 5x

Solve x:

The sum of angles in a triangle is 180º

3x + 4x + 5x = 180

12x = 180

x = 180 ÷ 12

x = 15º

Find the angles:

3x = 3(15) = 45º

4x = 4(15) = 60º

5x = 5(15) = 75º

Answer: The angles are 45º, 60º and 75º