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2.11 Inverse operation with sine
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What if we know the hypotenuse is 1 m long?
| Side Opposite 30°
| ?
| 1 m
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| hypotenuse
| 1 m
| 2 m
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The side opposite 30° is half the length of the hypotenuse, so if the hypotenuse is 1 m, the side opposite 30° is 0.5 m.
| Side Opposite 30°
| 0.5 m
| 1 m
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| hypotenuse
| 1 m
| 2 m
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Get learners to key sin 30° into their calculators. Calculator returns 0.5. So the calculator is telling us the ratio of side opposite 30° to hypotenuse is 0.5 : 1. Or if we look at the ratio in fractional form:
. If learners see this as a ratio rather than just a decimal number it makes it much easier for them to solve problems using sine (same for cosine and tangent).
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