Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
Chapter Review
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Exercise 36 Page 423

Notice that for a kite the diagonals are perpendicular.

m∠ 1 = 56
m∠ 2 = 52

Practice makes perfect

Let's find the measures of the numbered angles one at a time.

Measure of ∠ 1

Before we begin, let's name the vertices of our kite. We will call it quadrilateral ABCD. The point of intersection between the diagonals we will label M.

If a quadrilateral is a kite, then its diagonals are perpendicular. Therefore, ∠ AMB is right and its measure is 90.
Let's study △ AMB. By the Triangle Angle-Sum Theorem we know that the measures of the angles add to 180. 34+ m∠ 1+90=180 Let's solve the equation!
34+ m∠ 1+90=180
Solve for m∠ 1
124+ m∠ 1=180
m∠ 1=56

Measure of ∠ 2

We see that △ ADC is an isosceles triangle. By the Isosceles Triangle Theorem we know that base angles are congruent. ∠ DAM ≅ ∠ DCM By the definition of congruence their measures are equal. Therefore, we have that m∠ DCM=38.

We can now look at the △ DCM. By the Triangle Angle-Sum Theorem we know that the measures of the angles add to 180. m∠ DCM+ m∠ CMD+m∠ 2=180 Since ∠ CMD is formed by the diagonals it is right and its measure is 90. By using that and that m∠ DCM=38, we can find the measure of angle 2.
m∠ DCM+ m∠ CMD+m∠ 2=180
38+ 90+m∠ 2=180
Solve for m∠ 2
128+m∠ 2=180
m∠ 2=52