McGraw Hill Integrated II, 2012
MH
McGraw Hill Integrated II, 2012 View details
6. Inequalities in Two Triangles
Continue to next subchapter

Exercise 34 Page 461

Focus on triangle △ YZW.

m∠ ZUY>m∠ ZUW

Practice makes perfect

Let's mark the angles we are asked to compare.

Notice that ZY=ZW. This means that triangle △ ZYW is isosceles, so angles ∠ ZWY and ∠ ZYW are congruent.

We can add the two angle measures given on the figure to find the measure of the angle at Z. m∠ YZW=45+55=100 We can use the Triangle Angle Sum Theorem in triangle △ ZYW to find the measure of these two congruent angles.
m∠ Z+m∠ Y+m∠ W=180
100+ m∠ W+m∠ W=180
Solve for m∠ W
100+2m∠ W=180
2m∠ W=80
m∠ W=40
This result also gives that m∠ Y=40. Let's put these measures on the figure.

We can now use the Triangle Angle Sum Theorem in triangles △ ZUY and △ ZUW to find the measure of the angles we are asked to compare. m∠ ZUY+45+40=180 &⟹ m∠ ZUY=95 m∠ ZUW+55+40=180 &⟹ m∠ ZUW=85 We are now ready to write the inequality we were asked to find. 95>85 ⇓ m∠ ZUY> m∠ ZUW