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3.02 Ratios of sides and angles of right-angled triangles

Worksheet
Sides of a right-angled triangle
1

Consider the following right-angled triangle:

Identify:

a
The opposite side to the angle \theta.
b
The adjacent side to the angle \theta.
c
The opposite side to the angle \alpha.
d
The adjacent side to the angle \alpha.
e
The angle opposite the hypotenuse.
2

Consider the following right-angled triangle:

a

Which angle is opposite the hypotenuse?

b

Which side is opposite \angle B?

c

Which side is adjacent \angle C?

3

During a particular time of the day, a tree casts a shadow of length 24\text{ m}. The height of the tree is estimated to be 7\text{ m}.

In the given triangle, state whether the height of the tree or the shadow of the tree is:

a

The opposite side to the angle \theta.

b

The adjacent side to the angle \theta.

Ratios of sides
4

With reference the angle \theta, find the value of these ratios for each of the following triangles:

i

\dfrac{\text{Opposite }}{\text{Adjacent }}

ii

\dfrac{\text{Opposite }}{\text{Hypotenuse }}

iii

\dfrac{\text{Adjacent }}{\text{Hypotenuse }}

a
b
c
d
e
f
5

Consider the given triangle:

a

For \angle ACB, find the value of the ratio \\ \dfrac{\text{opposite}}{\text{hypotenuse}}.

b

For \angle CAB, find the value of the ratio \\ \dfrac{\text{adjacent}}{\text{hypotenuse}}.

6

Consider the given triangle:

a

For \angle ACB, find the value of the ratio \\ \dfrac{\text{adjacent}}{\text{hypotenuse}}.

b

For \angle CAB, find the value of the ratio \\ \dfrac{\text{opposite}}{\text{hypotenuse}}.

7

Consider the following diagram:

With regards to the angle \theta, find the value of the following ratios:

a
\dfrac{\text{adjacent}}{\text{hypotenuse}}
b
\dfrac{\text{opposite}}{\text{hypotenuse}}
c
\dfrac{\text{opposite}}{\text{adjacent}}
8

Consider the following diagram:

Find the following ratio of sides, with respect to \theta:

a

\dfrac{\text{opposite}}{\text{adjacent}}

b

\dfrac{\text{adjacent}}{\text{hypotenuse}}

c

\dfrac{\text{opposite}}{\text{hypotenuse}}

9

Consider the diagram below:

a

Using the triangle created by the building, find the value of the fraction \dfrac{\text{opposite}}{\text{adjacent}} using the opposite side and adjacent adjacent side of \angle TAB.

b

The tree has a height of 21 metres. For the smaller triangle created by the tree, find the value of the fraction \dfrac{\text{opposite}}{\text{adjacent}} using the opposite side and adjacent adjacent side of \angle HAC.

c

Are the ratios from (a) and (b) equal?

d

Using the triangle created by the tree, find the value of the fraction \dfrac{\text{adjacent}}{\text{hypotenuse}} using the adjacent side and hypotenuse for \angle HAC.

e

Using the triangle created by the building, find the value of the fraction \dfrac{\text{opposite}}{\text{hypotenuse}} using the opposite side and hypotenuse for \angle TAB.

f

Are the ratios from (d) and (e) equal?

Trigonometric ratios
10

Write down the following ratios for the given triangle:

a
\sin \theta
b
\sin \alpha
c
\cos \theta
d
\cos \alpha
e
\tan \theta
f
\tan \alpha
11

For the following triangles, determine \cos \theta:

a
b
12

Evaluate \sin \theta in the following triangles:

a
b
13

Find the value of \tan \theta in the following triangles:

a
b
14

Which trigonometric ratio ( \sin \theta, \cos \theta or \tan \theta) relates the given sides and reference angle in the following triangles?

a
b
c
d
15

For each of the following triangles:

i

Find the value of x.

ii

Find the value of \sin \theta.

iii

Find the value of \cos \theta.

a
b
16

For each of the following triangles:

i

Find the value of the missing side.

ii

Find the value of \tan \theta.

a
b
c
17

In the following triangle \sin \theta = \dfrac{4}{5}:

a

Which angle is represented by \theta?

b

Find the value of \cos \theta.

c

Find the value of \tan \theta.

18

In the following triangle \tan \theta = \dfrac{15}{8}.

a

Which angle is represented by \theta?

b

Find \cos \theta.

c

Find \sin \theta.

19

Consider the following triangle:

a

Find the value of \sin \theta.

b

Find the value of \cos \theta.

c

Find the value of \dfrac{\sin \theta}{\cos \theta}.

d

Find the value of \tan \theta.

e

Does \tan \theta = \dfrac{\sin \theta}{\cos \theta}?

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