Thread: Finding the length

I have an issue with this question that why in the solution 2 is multiplied to the radius of 6400.


The question is....

Q)the angle subtended by the earth at the eye of the spaceman landed on the moon is 1 degree 54 minute.The radius of earth is 6400 km.Find the approx distance b/w the moon and the earth.

Solution:

r=L/Theta
r=2*6400/0.033155

r=386065.45 km Ans

Hi

Since L is much bigger than r, we have

Since the angle is very low, we have

Therefore

cant understand u

Hello, haftakhan!

Did you make a sketch?

Q) The angle subtended by the earth at the eye of the spaceman
on the moon is 1 degree 54 minutes. The radius of earth is 6400 km.
Find the approx distance b/w the moon and the earth.

Code:

                                      *
                              *   *   | - *
                      *         *     |R    *
              *                *      |      *
      o        @               *      *      *
              *                *      |      *
                      *         *     |R   *
                              *   *   |   *
                                      *

Do you see why we use 2R ?


BTW, their answer is off.

1 degree, 54 minutes .= .1.9 degrees.

. . And 1.9 degrees = 0.033161256 radians.