In right-angled triangle (ABC ) with right angle at (B )

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

Problem

In right-angled triangle

ABC

with right angle at

B

, the side

AB

(adjacent to angle

A

) is

12\,\text{cm}

long and

\cos A = 0.8.

Use this information to answer the following. (i) Determine the lengths of sides

BC

and

AC

. (ii) Calculate the perimeter of

\triangle ABC.

(iii) Find the area of the triangle, giving your answer correct to one decimal place.