Trigonometry - Angles of elevation & depression.
Test Yourself 1 - Solutions.
Angles of elevation. | |
5. | |
Angle of depression. | 6. |
10. | |
Both types. | 11.
|
12. (i) Tan EFD = 254/37 = 81° 43' Angle of depression of D from F = 90° - 81°43' = 8° 7'. (ii) 165 = AE + EF = AF + 37 AF = 128 cm DC also equals 128 cm because ACDE is a rectangle. (iii) GB = 196 = 9 + 128 + CB CB = 59 cm. (iv) Tan CAB = 59/254 CAB = 13° 5' which is the angle of depresion of B from A. (v) FD is not parallel to AB - the angles differ by 4° 58'. (vi) The area ABDE is made up of a rectangle and a triangle. Arearectangle = 128 × 254 = 32,512 cm2. Arealower tri = 1/2 × 254 × 59 = 7493 cm2 Total = 40,005 cm2 = 4 0 m2 (because 1 m2 = 100 × 100 cm2 = 10,000 cm2. |
|