Question

Alex is making an isosceles triangle-shaped pennant to support her school’s athletic team on sports day as shown below. Side ac is the same length as side an . Alex rotates the pennant 90 degrees clockwise to stick it to the wooden pole

Answer 1

104°

Explanation:

The marked angles have the same measure, so ...

(4x +10) = (7x -11)

21 = 3x . . . . . . . . . . . add 11-4x

7 = x . . . . . . . . . . . . . divide by 3

Then angle C is ...

C = (4x +10)° = (4(7) +10)° = 38°

The measure of angle A is 180° -2(38°) = 104°.

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That angle will have the same measure whether the pennant is rotated or not.