Question

2. The moon's distance from the earth is 3,60,000 kms and its diameter subtends an
angle of 31' at the eye of the observer. Find the diameter of the moon.
ANSWERS​

Answer 1

Let AB be the diameter of moon.

we can consider the diameter of moon as arc because the distance between the earth and moon is large.

Let E be the observer.

Let d be the diameter of moon .

Then d=arcAB.

θ=42°

=(42/60)°

=[(42/60)xπ/180]

r=360000kms

θ=arc/radius

[(42/60)xπ/180]=d/360000

d=[42/60)xπ/180]x360000

d=0.7x0.017x360000=4398 km.

but the the actual diameter of moon is 3474km.

so in the given question the data is given wrong