From where Kiana is standing she must look up at a 50° angle to see the top of a building she backs up 50 feet she will need to look up a 40° angle to see the top of the same building approximately how tall is the building

For this case, what we must do is solve the following system of equations:  tan (50) = h / x  tan (40) = h / (x + 50)  

Solving the system we have:  (x + 50) * tan (40) = h  (x) * tan (50) = h  

Matching:  (x + 50) * tan (40) = (x) * tan (50)  

Rewriting:  x (tan (50) - tan (40)) = 50 * tan (40)  x = 50 * tan (40) / (tan (50) - tan (40))  x = 118.9692621  

Substituting:  h = (x) * tan (50)  h = (118.9692621) * tan (50)  h = 141.7820455

B. 141.8ft

Step-by-step explanation:

This is how you would proceed:

Centered at D, draw an arc of 7m (3.5cm) within the garden (rectangle).

Centered at B, draw an arc of 4m (2cm) within the garden.

There will be two intersection points, one is outside the garden (that you will not see), and the other is within the garden, which is where the tree should be planted.

See illustration attached.