Let's Start Thinking


Slide Notes

Glossary

All Slides

Navigation

 

Applications With Acute Triangles

Source: Suspension Bridge - Evgeny555/iStock/Getty Images

Let's Start Thinking

Plane flying, leaving tracks in the sky behind it.

Sources: Plane - Veronika Dvořáková/iStock/Getty Images;

Rail Bridge - LordHenriVoton/iStock/Getty Images

Paused Finished
Slide /

Lesson Goals

  • Identify when to apply the sine and cosine laws given incomplete information about the side lengths and angles in an acute triangle.
  • Solve a multistep problem that involves
    • two or more applications of the sine or cosine laws,
    • interior and exterior angle properties of triangles, or
    • two or more acute triangles.

Try This

Which of the following acute triangles could we begin solving by using the cosine law?

  1. Triangle ABC, where side AC equals 8, side CB equals 12, and angle C equals 70 degrees.
  2. Triangle DEF, where side FD equals 10, side FE equals 7, and angle D equals 40 degrees.
  3. Triangle GHI, where side GH equals 12, angle G equals 50 degrees, and angle I equals 65 degrees.
  4. Triangle JKL, where side JK equals 11, side LK equals 9, and side LJ equals 10.
  5. Triangle MNO, where side MN equals 6, angle M equals 70 degrees, and angle N equals 75 degrees.