Answered

Westonci.ca is your trusted source for finding answers to a wide range of questions, backed by a knowledgeable community. Get immediate and reliable solutions to your questions from a community of experienced professionals on our platform. Our platform provides a seamless experience for finding reliable answers from a network of experienced professionals.


A telegraph pole stands on a line joining two points P and Q on the ground.
The telegraph pole is 9 m tall. The angle of depression of the top of the pole to point P
is 4°. The angle of depression of the top of the pole to point Q is 7º. What is the
horizontal distance between P and Q.


Sagot :

reinhard10158

Step-by-step explanation:

let's call the top of the pole T, and the ground point of the pole G.

so, the situation gives us 2 right-angled triangles:

PTG and QTB.

from both triangles we know one leg (TG, the pole = 9 m), the inner angles at G (90° in both cases), and actually the inner angles at T, because we know the angles of depression there.

the inner triangle angles at T are just the complementary angles of the angles of depression (that means they add up together to 90°).

the inner angle at PTG = 90 - 4 = 86°

the inner angle at QTG = 90 - 7 = 83°

and because the sum of all angles in a triangle is always 180°, we even know the third angles at P and Q :

angle P = 180 - 90 - 86 = 4°

angle Q = 180 - 90 - 83 = 7°

yes, they are the same as the angles of depression (must be the same).

so, we know from both triangles 1 side and all 3 angles.

with the law of sine we can get every missing side.

particularly we need the second legs (sides in the ground) to get the distance between both points.

a/sin(A) = b/sin(B) = c/sin(C)

a, b, c being the sides always opposite of their related angles.

TG/sin(4) = PG/sin(86)

PG = 9×sin(86)/sin(4) = 128.7059963... m

TG/sin(7) = QG/sin(83)

QG = 9×sin(83)/sin(7) = 73.29911785... m

the distance between P and Q can have now 2 solutions :

if P and Q are on different sides of the pole, then

PQ = 128.7059963... + 73.29911785... = 202.0051142... m

but if they are on the same side of the pole, then their distance is

PQ = 128.7059963... - 73.29911785... = 55.40687846... m

due to the phrasing of the first sentence I suspect the first solution to be right.

but just in case, I gave you also the second possible solution.

Thanks for using our platform. We're always here to provide accurate and up-to-date answers to all your queries. We hope our answers were useful. Return anytime for more information and answers to any other questions you have. Stay curious and keep coming back to Westonci.ca for answers to all your burning questions.