TrigonometryTrigonometry

(Continued)(Continued)

S O H

C A H

T O A

What we know already!What we know already!

O

opp

Adj

Hyp O means theta

Find the missing lengthFind the missing length

Y1530°

Sin O = opposite

hypotenuse

Sin 30º = Y

15

0.5 = y

15

0.5 x 15 = Y

Y = 7.5

Finding angles when you know the lengths

Finding angles when you know the lengths

What if we know the length and want to find the angle?What if we know the length and want to find the angle?

O

14cm

17cm

Tan O = opposite

adjacent

Tan O = 14

17

Tan O = 0.8235

Angle O = inv tan 0.8235

Angle O = 39.47º

Using the inverse button on your calculator, work out the following angles

Using the inverse button on your calculator, work out the following angles

1) Sin = 0.6421

2) Cos = 0.7254

3) Tan = 0.2125

4) Cos = 0.9564

5) Tan = 0.5

6) Sin = 0.86247)

Tan = 0.5724

8) Sin = 0.8

9) Cos = 0. 9847

10) Tan = 0.7464

Please copy the diagrams and find the missing lengths

Please copy the diagrams and find the missing lengths

Y

25

XA

X

6.2

A

BC

X

A 25 B

20

25

B

12AC

C

BC

30º

30

70º 40º

23º50

30º

45º

6.5

40º

1

2

3

4

5

6

7

8