McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
4. Rectangles
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Exercise 13 Page 508

Recall that diagonals in a rectangle are congruent and bisect each other.

50

Practice makes perfect

We are asked to find the measure of ∠EDC using the given information. Let's notice that, since diagonals in a rectangle are congruent and bisect each other, AE=DE. This means that triangle AED is an isosceles triangle and m∠DAE=m∠ADE.

Recall that in a rectangle all four angles are right angles. Therefore, the sum of m∠ADE and m∠EDC is 90.

m∠ADE+m∠EDC=90
65+m∠EDC=90
m∠EDC=25

The measure of ∠EDC is 25.