How tall is that?

1.My group members is Dohyun and Kevin. 2.The building name is Science class building 3.Before taking measurements:I guess 9m and after taking measurements the building highest is 9.8m 4.I collected those measurements because these are helpful for the final result.And following is the process of collecting data. First, I guess this building is 9m and each floor is 3m. Second, use the Clinometer and measuring with the human eye as the endpoint and let the Clinometer another side align the top of the building. Then, measured angles between the level ground and r side degrees. Finally, measured the height of the BC and the height of the CE is CB+BE.