Wich method do you prefer to use to find sums-count by tens and ones, use compatible numbers ,or use friendly numbers and adjust ? explain why.

Can some one explain this i got sent this. is this a threat i’m scared

In the diagram, a building cast a 35-ft shadow and a flagpole casts an 8-ft shadow. if the the flagpole is 18 ft tall, how tall is the building? round the the nearest tenth.

Given the net of the rectangular prism, what is its surface area?