Support the Monkey! Tell All your Friends and Teachers

Help / FAQ

4. Find the approximate diameter of the moon if an observer on the earth measures an angle of 0.50 from the top to the bottom of the disk when the moon is 240.000 km away.


Let O be the eye of the observer. C is the centre of the moon, r be the distance from O to C, and DE be a diameter of the moon perpendicular to OC. Finally, Let A and B be the points where the circle of radius r centered at O intersects the moon. Then r is the approximate distance at O intersects the moon. Then r is the approx. distance from the earth to the moon, and DE is approx. S, where S = l (ACB).

Since r = 240,000 is probably accurate to only two significant figures. Thus the most we can say is that the diameter » 2100 km

5. Find the interior angles of a regular polygon of 10 sides in radians.


[next page]



1.1 Angles (Radians & Degrees)
1.2 Arc Length & Area of the circle
Supplementary Problems

Chapter 2

All Contents Copyright © All rights reserved.
Further Distribution Is Strictly Prohibited.

In Association with