Sine for SQA National 5 Maths

Sine

This page covers the following topics:

1. Sine
2. Values and applications
3. Right-angled traingles

Sine of an angle is a ratio between the side opposite to the angle and the hypotenuse of a triangle.

Sine

Sine is one of three trigonometric functions of an angle.

Values and applications

sin(x) is calculated by calculating the ratio of two sides of a right-angled triangle, the opposite and the hypotenuse.

Right-angled traingles

1

Find the value of sin(A) by using the triangle shown.

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0.62

Find the value of sin(A) by using the triangle shown.

2

Find sinB if b = 5 and c = 25.

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1/5 or 0.2

Find sinB if b = 5 and c = 25.

3

Use your calculator to find the value of sin(60º).

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0.87

Use your calculator to find the value of sin(60º).

4

Which side of the triangle shown is the opposite?

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b

Which side of the triangle shown is the opposite?

5

Find sinA if a = 7 cm and c = 10 cm.

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7/10 or 0.7

Find sinA if a = 7 cm and c = 10 cm.

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