Question

a surveyor measures the distance to the two landmarks as shown in the diagram what is the distance d. between the landmarks​

Answer 1

The distance between two landmarks is 123 meters

Solution:

We have to find the distance between two landmarks

Use the law of cosines

The third side of a triangle can be found when we know two sides and the angle between them

$c^2 = a^2 + b^2 - 2ab\ cos c$

Here, angle between 90 meters and 130 meters is 65 degrees

From figure,

a = 90

b = 130

c = d

Therefore,

$d^2 = 90^2 + 130^2 - 2(90)(130)\ cos 65\\\\d^2 = 8100 + 16900 - 23400\ cos\ 65\\\\d^2 = 25000 - 23400 \times 0.4226\\\\d^2 = 25000 - 9889.267\\\\d^2 = 15110.73\\\\d = 122.92\\\\d \approx 123$

Thus, the distance between two landmarks is 123 meters