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://img.qammunity.org/2023/formulas/mathematics/college/4ojvsm3aplv5xrgsm5xd7v3f87t522wuyy.png)
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°