The moon distance from the earth is 360000 km and it's diameter subtends an angle of 42' at the eye of the observer. The diameter of moon in km is
Moon's distance from Earth=360000 km
Angle= 42' =[42/60 × 1/180] radian
Therefore, diameter of moon= 42/60 × 22/7 × 1/180 × 360000 = 4400 km