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Back to Prove theorems about triangles — Problem 3 · Task Set 10

Exercises: Prove Theorems About Triangles

Work through each section in order. Show your reasoning for proof-based problems.

Grade 9·21 problems·~35 min·Common Core Math - HS Geometry·standard·hsg-co-c-10
Work through problems with immediate feedback
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Fluency Practice

Apply the triangle theorems directly to find missing values.

Isosceles triangle ABC with vertex angle 50° at A and equal legs AB = AC. The base angle at B is unknown.
1.

Isosceles triangle ABCABC has AB=ACAB = AC. The vertex angle measures ∠A=50∘\angle A = 50^\circ. Find m∠Bm\angle B.