Question

The measure of angle of a triangle are x°,(x-20)°,(x-40)°.
Find the measures of each angle

Answer 1

the angles are x, x - 20 and x - 40
therefore,
Angle (1+2+3) = 180
x + x -20 + x -40= 180
3x - 60 = 180
3x = 240
x = 80
hence, each angles are 80°, 60° and 40°.....

Answer 2

Sum of angles in a triangle = (n-2)× 180° where n is the number of side

Number of sides in a triangle = 3
Sum of interior angles=( 3-2)× 180° = 180°

Given that,
1st angle = x°
2nd angle (x - 20)°
3rd angle = (x-40)°

So, an equation will be formed

x° + x° - 20° + x° - 40° = 180°

regrouping the terms in LHS ,
we have,

x° + x° + x° - 20° - 40° = 180°

3x° - 60° = 180°

3x = 180° + 60°

3x = 240°

$x = \frac{240}{3}$

x = 80

So,

1st angle = x = 80°
2nd angle = x -20° = 80° - 20° = 60°
3rd angle = x - 40° = 80° - 40° = 40°

Thus,

the angles of the given triangle 80° , 60° and 40°