From point A,the angle of elevation to the top of a tall building is 20 degrees.On walking 80 m towards the building,the angle of elevation is now 23 degrees.How tall is the building?

Answer 1

Make a sketch, label the top of the building P and its bottom Q.
On the ground, label angle A = 20 and mark point B as 23 degrees
then angle ABP = 180-23 = 157 degrees
angle A = 20 and angle APB = 3 degrees
by the sine law
BP/sin20 = 80/sin3
BP = 80sin20/sin3
= ....

then in the right-angled triangle BPQ
sin 23 = PQ/BP

take over

Answer 2

h= 220.95m

Answer 3

stanley u are wrong the answer is 204.1m