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Problem 180

Geometry Difficulty 1.3 Multiple choice CEMC Gauss (Grade 8) · Canada · 2024

In the diagram, $\angle ABC$ is a straight angle.The value of $x$ is

Pick one

Official solution

Since the measure of a straight angle is 180 $\degree$ , then $40\degree + x\degree + x\degree = 180\degree$ .

Solving this equation, we get $40+x+x=180$ or $2x=140$ , and so $x=70$ .

Figure for this problem

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty, ordering) added by this project.