A lamp-post is tall

MATHEMATICS · Multi-part · CBSE · Mathematics · Introduction to Trigonometry · Introduction to Trigonometry

Problem

A lamp-post

PQ

15\,\text{m}

tall. A wire joins the top of the lamp-post

P

to a point

R

on the ground such that the wire makes an acute angle

\theta

with the horizontal line

QR

. It is given that

\sin \theta = \dfrac{5}{13}

. (i) Find

\cos \theta

. (ii) Determine the length of the wire

PR

. (iii) Calculate the distance

QR

between the foot of the lamp-post and the point

R