# Geometry - Practice Problem

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The Triangle is 30 degrees , -60 degrees, -90 degrees. Triangle ABC .A is at the top measuring 60 degrees, B is measuring 30 degrees and C is at the right angle.

If b = 7cm , find a.

https://brainmass.com/math/triangles/geometry-practice-problem-191449

## SOLUTION This solution is **FREE** courtesy of BrainMass!

In this triangle, since two of the three sides are unknown, we cant use Pythagoras Theorem. We solve this question using

basic Trigonometry.

In triangle ABC, we have tan A = a/b

Since b = 7, and angle A = 60 degrees, tan 60 deg = a/7

a = 7 tan 60 = 7 * sqrt 3 = 12.12 cm (Approximately).

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