We are given that ΔABC is isosceles with AB ≅ AC. Using the definition of congruent line segments, we know that .
We are given that ∠B ≅ ∠C. Assume segment AB is not congruent to .
Adjust point D so the measure of angle BAD is equal to the measure of angle CAD. Which statements are true? Check all that apply.AD bisects ∠BAC. AD bisects BC.AD forms right angles with BC.AD is perpendicular to BC.AD is the perpendicular bisector of BC.
Let’s assume that angles B and C are not congruent. Then one angle measure must be greater than the other. If m∠B is greater than m∠C, then AC is greater than AB by the .
If AB > AC, then m∠C > m∠B by the . If AB < AC, then m∠C < m∠B by the converse of the triangle parts relationship theorem.
However, this contradicts the given information that . Therefore, , which is what we wished to prove.
But by the definition of congruent, we know the measure of angle B equals the measure of by the given statement. Therefore, we have a contradiction: AB = AC, and AB ≅ AC.
However, this contradicts the given information that . Therefore, , which is what we wished to prove.
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