Using the sine ratio
I can use the sine ratio to find the missing side or angle in a right-angled triangle.
Using the sine ratio
I can use the sine ratio to find the missing side or angle in a right-angled triangle.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- The sine ratio involves the hypotenuse, opposite and the angle.
- If you know the length of the hypotenuse and the size of the angle, you can use the sine ratio.
- If you know the length of the opposite and the size of the angle, you can use the sine ratio.
- If you know the length of the hypotenuse and opposite, you can use the sine ratio.
Keywords
Hypotenuse - The hypotenuse is the side of a right-angled triangle which is opposite the right angle.
Opposite - The opposite side of a right-angled triangle is the side which is opposite the marked angle.
Trigonometric function - Trigonometric functions are commonly defined as ratios of two sides of a right-angled triangle for a given angle.
Sine function - The sine of an angle (sin(θ°)) is the y-coordinate of point P on the triangle formed inside the unit circle.
Common misconception
The sine formula is only used to find the length of a side opposite an angle.
Whilst the sine formula can be used to find the length of a side opposite an angle, a rearrangement of the formula also allows us to find the length of the hypotenuse given the opposite side. The arcsine function allows us to find the angle, itself.
To help you plan your year 9 maths lesson on: Using the sine ratio, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 9 maths lesson on: Using the sine ratio, download all teaching resources for free and adapt to suit your pupils' needs.
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