(a) PQRST is a circle with centre C. PCS is a straight line, RS // QT, |QR| = |RS| and < QTS = 56°. Find (i) SQT (ii) PQT. (b) In the diagram, points B and C are on a horizontal plane and |BC| = 30cm. A and D are points vertically above B and C respectively. |DC| = 40 cm and |AB| = 26 cm. Calculate the angles of depression of : (i) B from D ; (ii) A from D ; correct to the nearest degree.
Explanation
(a) From the figure < QRS = 180° - 56° = 124° (opposite angles of a parallelogram) < RQS = < PQS = (base angles of an isosceles triangle) < SQT = < RSQ = 28° (alternate angles PS // QT) (ii) < PQT = 90° - 28° = 62° (< PQS is in a semi-circle) (b)
