Q8.

In triangle [tex]\( RPQ \)[/tex]:
- [tex]\( RP = 8.7 \)[/tex] cm
- [tex]\( PQ = 5.2 \)[/tex] cm
- [tex]\(\angle PRQ = 32^\circ \)[/tex]

(a) Assuming that [tex]\(\angle PQR\)[/tex] is an acute angle, calculate the area of triangle [tex]\( RPQ \)[/tex].
Give your answer correct to 3 significant figures.



Answer :

To solve for the area of triangle RPQ, we will use the formula for the area of a triangle when two sides and the included angle are known:

[tex]\[ \text{Area} = \frac{1}{2} \times a \times b \times \sin(C) \][/tex]

where:
- [tex]\( a \)[/tex] and [tex]\( b \)[/tex] are the lengths of two sides of the triangle
- [tex]\( C \)[/tex] is the included angle between those sides

Given in the problem:
- RP = 8.7 cm
- PQ = 5.2 cm
- Angle PRQ = 32°

We'll follow these steps:

1. Convert the angle from degrees to radians:
[tex]\[ \text{Angle PRQ in radians} = \frac{32 \times \pi}{180} \][/tex]
This gives an angle of approximately 0.5585053606381855 radians.

2. Calculate the area using the given formula:
[tex]\[ \text{Area} = \frac{1}{2} \times 8.7 \times 5.2 \times \sin(0.5585053606381855) \][/tex]
This results in an area of approximately 11.986773756955094 square centimeters.

3. Round the area to 3 significant figures:
[tex]\[ \text{Rounded Area} = 11.987 \][/tex]

Therefore, the area of triangle RPQ, correct to 3 significant figures, is 11.987 square centimeters.