Answer:
x = 115°
Step-by-step explanation:
We know that a triangle has 180° in total when you add up all the interior angles. So in order to find the value of x°, we need to find the missing angle in the triangle itself:
180°-(75°+40°)
= 180° - 115°
= 65°
To find x°, we know that the 65° angle + x° is equal to 180° because it's a supplementary angle. So:
x° + 65° = 180°
x° = 115°
