Question

From points a and b on level ground the angles of elevation of the top of a building are 25degree and 37 degree respectively. if [ab] =57m, calculate to the nearest metre, the distances of the top of the building from a and b if they are both on the same side of the building

Answer 1

The distance of the top of the building from a is 163m and that from b is 115m .

Calculating the Perpendicular Distance of the Top From Ground

It is given that the angle of elevations of the building top from a and b are 25° and 37° respectively.

ab = 57m

Let the top of the building be point c and the distance between the building and the point b be x. Then, from the figure, we can deduce the following,

In Δacd, tan 25° = cd/ad

⇒ 0.4663 = cd /(x+57)

⇒ cd = 0.4663(x+57)             ......................... (1)

In Δbcd, tan 37° = cd/x

⇒ 0.7536 = cd/x

⇒ x =cd / 0.7536                   .......................... (2)

Solving for the Distance cd

Substitute the value of in equation (2) to equation (1) to get,

cd = 0.4663 ((cd/0.7536)+57)

cd = 0.4663(cd+42.9552)/0.7536

0.7536cd = 0.4663cd + 20.03

0.7536cd - 0.4663cd = 20.03

0.2906cd = 20.03

cd = 20.03/0.2906

Thus, the distance cd ≈ 68.93m

Finding the Distance cb and Distance ca

In Δacd, sin25° = cd/ca

⇒ 0.4226 = 68.93/ca

ca = 68.93/0.4226

ca = 163.10

∴ The distance ca ≈ 163m

Similarly, in Δbcd, sin37° = cd/cb

⇒ 0.6018 = 68.93/cb

cb = 68.93/0.6018

cb =114.54m

∴ The distance cb ≈ 115m

Therefore, the points a and b are at a distance of 163m and 115m respectively from the top of the building.  

Learn more about distance here:

brainly.com/question/25263797

#SPJ4