8. The diagram shows a suspension bridge across a river. Each of the triangular pieces of the bridge are identical.
The base angle of each triangle is 34° and the perpendicular height of each triangle is 16m.
Calculate the length of the bridge, correct to two decimal places.
9. The diagram shows a goalpost that has snapped in two during a storm. The top of the post is now lying 15 m from the base at an angle of 25°. Calculate the height of the goal post, to the nearest metre, before it snapped in two.
34°
34°
25° 15 m
10. An airplane climbs at an angle of 18° with the ground. Find the ground distance the plane has travelled when it has moved 2 500 m through the air. Give your answer to two signifi cant fi gures.
34B Taking it FURTHER
1. Find the length of the side p and the measure of the angle m in the diagram shown. Give your answer to the nearest degree.
15 47° p 18 m° 64°
2. Find the value of the angle marked x in the diagram. P
10 S x 65° R
3. A passenger in a plane is told that the plane is fl ying at a height of 4 000 m and is 15 km from the airport.
What is the angle of depression from the plane to the airport? Give your answer to the nearest degree.
Sophie 19° 5 m
(i) How tall is the tree? Give your answer to the nearest metre.
Q 3
(ii) Use the information to estimate Sophie’s height, giving your answer to the nearest centimetre.
(iii) What further information is needed to accurately calculate Sophie’s height?
4. Sophie stands 5 m from a tree. From her eye level, the angle of depression of the base of the tree is 19° and the angle of elevation to the top of the tree is 64°.