Definition: A right triangle is a triangle with exactly one 90 degree (right) angle. A right angle is indicated with a “box” or “square” symbol at the angle’s vertex.
A right triangle can also be isosceles if the two sides adjacent to the right angle are congruent.
Example: Find the measure of ∠x:
Solution: Use the information provided in the figure to solve for ∠x.
Step 1: We can determine from the figure’s markings that this is a right triangle with one 20 degree angle. Keeping the Triangle Sum Theorem in mind (the sum of a triangle’s interior angles equals 180 degrees), we can write the following equation to find x:
90 + 20 + x = 180
Step 2: Solve for x
110 + x = 180
x = 70°, so the right triangle’s missing angle is equal to 70°.
Still need help identifying right triangles? Download Yup and get help from an expert math tutor 24/7.