Assuming that angles X and Z are the same as A and C, the Y angle must be 75 degrees. It's because the sum of all three angles in any triangle give us 180 degrees, so:
180 - 45 - 60 = 75 degrees
a) Due to you have a right triangle, in order to calculate the value of d, use the Pythagorean thorem:
![d=\sqrt[]{(60m)^2+(20m)^2}=\sqrt[]{4000m^2}\approx63.2m](https://tex.z-dn.net/?f=d%3D%5Csqrt%5B%5D%7B%2860m%29%5E2%2B%2820m%29%5E2%7D%3D%5Csqrt%5B%5D%7B4000m%5E2%7D%5Capprox63.2m)
Hence, the distance d is approximately 63.2m
b) To find the angle of elevation, use the sine function of θ, as follow:

Hence, the angle of elevation is approximately 19.8°
Circumference = pi * diameter = 21 * 22/7 = 66 m (answer)
6.3 minutes: 6 minutes and 20 seconds, I believe.