Trig 2.1 - 2.3 Review

Find the exact value of sin(30°). DO NOT USE A CALCULATOR.

• 1/2
• √3/2
• √2/2
• 1

Tags

CCSS.HSF.TF.A.2

• A
• B
• C
• D

Answer explanation

Subtract 360 to get 320. Then the x-axis is another 40 degrees to get to 360, so 40 degrees is the reference angle.

What is the reference angle of 240°?

• 30^o
• 45^o
• 60^o
• 90^o

Find the exact value of cosine 135º. DO NOT USE A CALCULATOR.

• - √2/2
• √2/2
• - √3/2
• 0

Answer explanation

Find your reference angle (rotation to the x-axis). It's 45 degrees, so use your 45-45-90 special triangle. Be sure your x (horizontal distance) is negative since we're going to the left.

Tags

CCSS.HSF.TF.A.2

Find cos(300 degrees). DO NOT USE A CALCULATOR.

• A
• B
• C
• D

Answer explanation

Find the reference angle -- it's 60 degrees to the x-axis. Then use your 30-60-90 special triangle. The vertical/y should be negative in QIV.

Tags

CCSS.HSF.TF.A.2

What is the cosine of angle P?

• p/q
• q/r
• p/r
• r/q

Answer explanation

Cosine is adj/hyp.

So side q is adjacent and the hypotenuse is r.

Tags

CCSS.HSG.SRT.C.6

Find x.

• 10
• √3
• 5
• 10√3

Answer explanation

Set up a ratio using your 30-60-90 triangle.

x/1 = 10/2

(or x=1 = 5√3/√3)

so x = 5.

Tags

CCSS.HSG.SRT.C.8

What is the value of x?

• 18√2
• 18
• 2√9
• 9√2

Answer explanation

Set up a ratio with the 45-45-90 triangle (or use Pythag. Thm)

x/1 = 18/√2

x = 9√2

Tags

CCSS.8.G.B.7

Find the measure of the indicated angle.

• 9.39°

• 55.2°

• 20.2°

• 19.4°

Answer explanation

We have the side opposite angle "?" and the hypotenuse, so use sine.

sin(?) = 23/28

sin^-1(23/28)

Tags

CCSS.HSG.SRT.C.8

Answer explanation

Find sin(42°). Then take the reciprocal.

Tags

CCSS.HSF.TF.A.2