Using Trigonometry to Solve for Missing Sides

Using Trigonometry to Solve for Missing Sides

Applying Trig Functions-Day 1

Using Trig to Find the Length of a Missing Side

STEP 1:

Label your Sides: Opposite, Adjacent, Hypotenuse

*Highlight your reference angle.

* Label Opposite, Adjacent, Hypotenuse (You can use O, A, and H for short!)

Decide:

Which Side Do I Know?

Which Side am I Solving For?

You have a measure for the hypotenuse. You want to solve for the adjacent side. Which trig function uses adjacent and hypotenuse? cos!

Set Up Your Equation!

Solve the equation for x.

You're ALMOST done!

Calculator Time!

A. Click on the wrench in the upper right corner. Click on Degrees. SUPER IMPORTANT!

B. Click on Keyboard icon- then FUNCTIONS, then TRIG.

C. Enter trig expression.

D. Round to the nearest tenth (one decimal place).

Multiple Choice

Which trig function will you need to use to solve for x?

• sin

• cos

• tan

Multiple Choice

Which equation will correctly solve for x?

• $\tan\left(78\right)=\frac{18}{x}$

• $\cos\left(78\right)=\frac{x}{18}$

• $\tan\left(78\right)=\frac{x}{18}$

• $\cos\left(78\right)=\frac{18}{x}$

Multiple Choice

Find the value of x. Round to the nearest tenth.

• 3.7

• 3.8

• 84.7

• 86.6

Multiple Choice

Which trig function will be used to solve for x?

• sin

• cos

• tan

Multiple Choice

Which equation should be used to correctly solve for x?

• $\sin\left(52\right)=\frac{38}{x}$

• $\cos\left(52\right)=\frac{38}{x}$

• $\sin\left(52\right)=\frac{x}{38}$

• $\cos\left(52\right)=\frac{x}{38}$

Multiple Choice

Find the value of x.

• 23.4

• 29.9

• 48.2

• 61.7