1. STARTER x x In each triangle, find the length of the side marked x.
55 mm x 40 mm
164 cm x
230 cm
In each triangle, find the length of the side marked x.
If required, round your answers to 1d.p.
13 mm x 5 mm
144 cm x
60 cm
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2. STARTER x x x x 230 cm 164 cm 40 mm 55 mm 13 mm 60 cm 5 mm 144 cm 68mm
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3. Using Trigonometric Ratios Introducing the Sine Ratio
Trigonometry
Using Trigonometric Ratios
Introducing the Sine Ratio
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4. Right-angled triangles
A right-angled triangle contains a right angle!
The side opposite the right angle is called the hypotenuse. This is the longest side.
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5. The opposite and adjacent sides
The side opposite the given angle is named the opposite side. x
The side next to the given angle (that is not the hypotenuse) is named the adjacent side.
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6. Name all the sides from the given angle, x
2).
1).
3).
4).
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7. The sine ratio The ratio of : the length of the opposite side
the length of the hypotenuse
is called the sine ratio.
sin x =
opposite
hypotenuse O P S I T E H Y P O T E N U S x
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8. = 6 × 0.5 = 3 cm a In this triangle, opposite sin 30° = hypotenuse a =
So, a = 6 × Sin 30
= 6 × 0.5
= 3 cm
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9. 53°
28 cm
Try this: x
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10. 32°
42 cm
Try this: x
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