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# C2 The sine and cosine rules watch

1. Hi, I have a problem with this question... can you help me only using sin and cos, please?

A tower stands on a slope inclined at 18° to the horizontal. From a point lower down the slope and 150 m from the base of the tower, the angle of elevation of the top of the tower is 9.5°. Find the height of the tower.
2. (Original post by maggyxxp)
Hi, I have a problem with this question... can you help me only using sin and cos, please?

A tower stands on a slope inclined at 18° to the horizontal. From a point lower down the slope and 150 m from the base of the tower, the angle of elevation of the top of the tower is 9.5°. Find the height of the tower.
What have you tried?
3. we have to assume that the tower is vertical, not perpendicular to the slope....
4. Wouldn't the angle of elevation have to be greater than 18 or am I being stupid?
5. Attachment 613640613646After drawing a rough diagram from the angles you've already been given you can go on to draw in some right angled triangles and figure out some more of the angles. Once you have found the angle opposite the 150m length you can use the sine rule (a/sinA = b/sinB) to say that 150/sin62.5 = a/sin9.5 where a is the height of the tower. You can then rearrange to find a and hence the height of the tower.
Attached Images

6. I found that h= 27,9m. Is that right?

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