📐 Trigonometry: Angles of Elevation & Depression

IGCSE — Word Problems with Metric Units
Created by Miss Clarissa Ng · www.clartutors.com

Key Formulas & Definitions

Section A — Angles of Depression

Q1. A boat is heading towards a lighthouse, whose beacon light is 45 m above the water. The boat's crew measures the angle of elevation from the deck to be 30°. What is the ship's horizontal distance from the lighthouse? Round your answer to the nearest hundredth of a metre.

30° 45 m distance = ?

Q2. From a hot air balloon, Yvonne measures a 25° angle of depression to a landmark that is 515 m away horizontally. What is the balloon's vertical distance above the ground? Round your answer to the nearest hundredth of a metre.

25° h = ? 515 m

Q3. From a hot air balloon, Dave measures a 39° angle of depression to a landmark that is 228 m away horizontally. What is the balloon's vertical distance above the ground? Round your answer to the nearest tenth of a metre.

39° h = ? 228 m

Q4. From the observation deck of a skyscraper, Mike measures a 68° angle of depression to a ship in the harbour below. If the observation deck is 347 m high, what is the horizontal distance from the base of the skyscraper out to the ship? Round your answer to the nearest tenth of a metre.

68° 347 m distance = ?

Q5. From the observation deck of a tower, Sarah measures a 72° angle of depression to a car on the road. If the observation deck is 350 m high, what is the horizontal distance from the base of the tower to the car? Round your answer to the nearest tenth of a metre.

72° 350 m distance = ?

Q6. From a hot air balloon, a pilot measures a 30° angle of depression to a landmark that is 444 m away horizontally. What is the balloon's vertical distance above the ground? Round your answer to the nearest tenth of a metre.

30° h = ? 444 m
Section B — Angles of Elevation

Q7. Dennis is flying a kite, holding his hands at a height of 1.5 m above the ground and letting out all the kite's string. He measures the angle of elevation from his hand to the tip of the kite to be 52°. If the string from the tip to his hand is 30 m long, how many metres in the air does the kite fly? Round your answer to the nearest hundredth of a metre.

30 m 52° 1.5 m total h :

Q8. Owen is flying a kite, holding his hands at a height of 1.2 m above the ground and letting out all the kite's string. He measures the angle of elevation from his hand to the tip of the kite to be 66°. If the string from the tip to his hand is 30 m long, how many metres in the air does the kite fly? Round your answer to the nearest hundredth of a metre.

30 m 66° 1.2 m total h

Q9. A 120 m tall communications tower casts a shadow. If the angle of elevation from the tip of the shadow to the top of the tower is 45°, how far is the tip of the shadow from the base of the tower? Round your answer to the nearest metre.

45° 120 m distance = ?

Q10. A surveyor stands 2.5 km from the base of a hill and measures the angle of elevation to the summit as 8°. How tall is the hill? Round your answer to the nearest metre.

8° h = ? 2.5 km
Section C — Ladder Problems

Q11. Alexander leans a 6 m ladder against a wall so that it forms an angle of 80° with the ground. How high up the wall does the ladder reach?

80° 6 m h = ?

Q12. A rescue worker leans an 8.5 m ladder against a building so that it forms an angle of 69° with the ground. How high up the wall does the ladder reach?

69° 8.5 m h = ?

Answer Key

Section A — Angles of Depression

Q1. tan 30° = 45 / distance → distance = 45 / tan 30° = 77.94 m
Q2. tan 25° = h / 515 → h = 515 × tan 25° = 241.37 m
Q3. tan 39° = h / 228 → h = 228 × tan 39° = 185.0 m
Q4. tan 68° = 347 / distance → distance = 347 / tan 68° = 142.5 m
Q5. tan 72° = 350 / distance → distance = 350 / tan 72° = 112.8 m
Q6. tan 30° = h / 444 → h = 444 × tan 30° = 256.3 m

Section B — Angles of Elevation

Q7. sin 52° = h_string / 30 → h_string = 30 × sin 52° = 23.74 m; total height = 23.74 + 1.5 = 25.24 m
Q8. sin 66° = h_string / 30 → h_string = 30 × sin 66° = 27.43 m; total height = 27.43 + 1.2 = 28.63 m
Q9. tan 45° = 120 / distance → distance = 120 / tan 45° = 120 m
Q10. tan 8° = h / 2500 → h = 2500 × tan 8° = 353 m

Section C — Ladder Problems

Q11. sin 80° = h / 6 → h = 6 × sin 80° = 5.9 m
Q12. sin 69° = h / 8.5 → h = 8.5 × sin 69° = 7.9 m