body{margin:0;} noscript{z-index: 10000; position: fixed; display: block; height: 100%; width: 100%; background: #fff;} noscript .fa{font-size: 40px; display:block; color: #daa520;} noscript div{margin-top: 6%; padding-left: 20px; padding-right: 20px; text-align: center;} ! You must have JavaScript enabled to use this site.

McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

5. Isosceles and Equilateral Triangles

Continue to next subchapter

Exercise 16 Page 379

Start by considering the Isosceles Triangle Theorem. Then use the Triangle Angle-Sum Theorem.

m∠ SRT=65

Practice makes perfect

Looking at the markings on the given figure, we can see that ST≅ RT.

To find m ∠ SRT, we will consider the Isosceles Triangle Theorem

Isosceles Triangle Theorem
If two sides of a triangle are congruent, then the angles opposite those sides are congruent.

Using this theorem, let's show the congruent angles and label them as x^(∘).

Now, we can find m ∠ SRT using the Triangle Angle-Sum Theorem.

m ∠ RST+m ∠ SRT+m ∠ RTS=180

SubstituteValues

Substitute values

x+x+50=180

Add terms

2x+50=180

LHS-50=RHS-50

2x=130

.LHS /2.=.RHS /2.

x=65

We found that the value of x is 65, so the measure of ∠ SRT is 65^(∘).

Subchapter links

Exercises p.378-382