Question

Find the value of x in a triangle. x-20, x+10, x-20

Answer 1

The value of the angles should be. (x-40°). , (x-20°), (½x-10°) , not (x-40°) + (x-20°)+(½x-10°)

Sum of all the interior angles of a triangle is 180°.

So a equation can be made by the given data,

(x-40°) + (x-20°) + (½ x-10°) = 180°

x-40°+x-20°+½x-10° = 180°

2x+½x -60°-10° = 180°

5/2 x - 70° = 180°

5/2 x = 180° + 70°

5/2 x = 250°

x = 250° × 2/5

x = 50° × 2

x = 100°

So the angles are

x-40° = 100°-40° = 60°

x-20° = 100°–20° = 80°

½x-10° = ½(100)° - 10° = 50° -10° = 40°

The answer can be checked by putting the values of the angle we got in the second statement i.e. Sum of all the interior angles of a triangle is 180°.

60° + 80° + 40° = 100° + 80° = 180°