Question

In a diagram showing two parallel lines cut by a trasversal, the measures of two same side interior angles are both given as 3x. Without writing and solving an equation, can you determine the measures of both angles? Explain. Then write and solve an equation to find the measures

Answer 1

90 degrees

Explanation:

Same side interior angles, or consecutive angles, are supplementary (angle measures add up to 180 degrees). Since both angles have measures 3x degrees, the angles are congruent (same angle measure). In Geometry, when two angles are congruent and supplementary, the two angles are right angles (angles measuring 90 degrees). Therefore the angle measures of the two angles are 90 degrees and 90 degrees.

Or, to solve this algebraically, add 3x and 3x, let it equal to 180 degrees, solve for x, and find the angle measures by substituting x into the expression.

3x + 3x = 180

6x = 180

x = 30

3x = 3*30 = 90