Question

A tower stand on a horizontal plane. P is the top and Q is the bottom of the tower. A and B are two points on this plane such that AB is 32m and QAB is a right angle. It is found that cot PA = 2/5 and cot PBQ = 3/5. Find the height of the tower.​

Answer 1

Answer:

32√5

Step-by-step explanation:

We have the right triangles PQA and PQB as well as the given right triangle QAB.

cot(PAQ) = 2/5 = QA/PQ

cot(PBQ) = 3/5 = QB/PQ

cot(PAQ) / cot(PBQ) = (2/5) / (3/5) = 2/3

cot(PAQ) / cot(PBQ) = (QA/PQ) / (QB/PQ) = QA / QB

QA / QB = 2/3

QA = (2/3) QB

QB = (3/2) QA

By the Pythagorean Theorem we have:

(QA)² + 32² = (QB)²

(QA)² + 32² = (3/2 QA)²

(QA)² + 1024 = (9/4) (QA)²

(5/4) (QA)² = 1024

(QA)² = (4/5)1024 = 4096/5

QA = 64/√5

Solve for PQ.

cot(PAQ) = QA/PQ

PQ = QA / cot(PAQ)

PQ = (64/√5) / (2/5) = 32√5

The height of the tower is 32√5.