Question

prove that the sum of three angles of a triangle is two right angles. if the angles are in the ratio 3 : 4 : 5, find the smallest angle

Answer 1

3x +4x +5x=180°
12x=180°
x=180/12
x=15

Answer 2

ratio of angles = 3:4:5
let Ist angle = 3x
let 2nd angle = 4x
let 3rd angle = 5x
ATQ:
3x + 4x + 5x = 180°
12x = 180°
x = 180°/12
x = 15
first angle = 3(15) = 45°
second angle = 4(15) = 60°
third angle = 5(15) = 75°
smallest angle = 45° = first angle
" the sum of angles of a triangle is two right angles " this statement is right because sum of angles of a triangle is 180° and right angle = 90° and two right angles = 90° + 90° = 180°