Question 79201
On problems involving triangles and unknown angles, you can use the well-known fact that the sum of the angles in any plane triangle is always 180 degrees.
So, set up the equation to add the given angles:
133 + (x+20) + (2x) = 180 Combine like-terms.
133 + 3x + 20 = 180 Simplify.
153 + 3x = 180 Subtract 153 from both sides.
3x = 27 Finally, divide both sides by 3.
x = 9 degrees.