Question

To estimate the height of a skyscraper 1km in the distance, Jenny finds that if her friend Steve stands 2.5 meters away, the top of his head just lines up with the top of the building. Steve is 2 meters tall, and Jenny's eye is 1.5 meters from the ground. How high is the building

Answer 1

The answer is below

Explanation:

Similar triangle are triangles with the same shape, equal pair of corresponding angles. Also they have the same ratio of the corresponding sides.

From the diagram attached, we can see that triangle ABC and triangle CEF are similar triangles. Hence:

AB/BC = CF/EF

Given that BC = 1 km = 1000 m, CF = 2 m - 1.5 m = 0.5 m, EF = 2.5 m.

Hence:

AB/1000 = 0.5/2.5

AB = (0.5/2.5) * 1000 = 200 m

The height of the building = AB + height of Steve = 200 m + 2 m

The height of the building = 202 m