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.

Big Ideas Math Geometry, 2014

BI

Big Ideas Math Geometry, 2014 View details

7. Law of Sines and Law of Cosines

Continue to next subchapter

Exercise 10 Page 513

Use the formula for finding the area of a triangle using sine, 12bc sin A.

≈ 333.5 square units

Practice makes perfect

We want to find the area of △ ABC.

To do so, we will use the formula for finding the area of a triangle using sine. Area=1/2bc sin A Since we are given that b= 28, c= 24, and m∠ A= 83^(∘), we can substitute these values into the formula to find the area. Let's do it!

Area=1/2bc sin A

SubstituteValues

Substitute values

Area=1/2( 28)( 24) sin 83^(∘)

▼

Simplify right-hand side

Multiply

Area=1/2(672) sin 83^(∘)

MoveRightFacToNumOne

1/b* a = a/b

Area=672/2 sin 83^(∘)

Calculate quotient

Area=336 sin 83^(∘)

Use a calculator

Area=336(0.992546... )

Multiply

Area=333.495456...

Round to 1 decimal place(s)

Area≈ 333.5

The area of △ ABC is about 333.5 square units.

Subchapter links

Communicate Your Answer p.507

Monitoring Progress p.508-512

Exercises p.513-516