trig q (1 Viewer)

[jimmysmith560]

From the top of a 200 m high building, the angle of depression to the bottom of a second building is 20°. From the same point, the angle of elevation to the top of the second building is 10°. Calculate the height of the second building in metres to 2 decimal places.

Would the following help?



AB is the building from which the second building CD is viewed.

Let CC’ and

Let H be the height of second building



Also, a reminder to please post maths-related threads in their appropriate forums.

 

[cossine]

unsure with drawing the diagram for this q
here’s my already sketched one and working out which i’m 100% sure is incorrect as my answer is also wrong

The diagram is a little bit off but mostly correct. The angle of depression or elevation is done with respect to a horizontal line. In your diagram 30 degrees would be the angle of depression instead of 20 degrees.

You will find the second building has greater height than the first due to the angle of elevation being 10 degrees.

I like how you have shown working out. Be careful about rounding. Don't round at intermediate steps as this can error in the final answer. E.g. 200tan(60) = 346.41

See how Jimmysmith only rounds at the end and uses the wavy equal sign to indicate the answer is an approximate.