(a) The angle of depression of a boat from the mid-point of a vertical cliff is 35°. If the boat is 120m from the foot of the cliff, calculate the height of the cliff.
(b) Towns P and Q are x km apart. Two motorists set out at the same time from P to Q at steady speeds of 60 km/h and 80 km/h. The faster motorist got to Q 30 minutes earlier than the other. Find the value of x.
(a)
In the diagram, < PQR = 125°, < QRS = r, < RST = 80° and < STU = 44°. Calculate the value of r.
(b) In the diagram TS is a tangent to the circle at A. AB // CE, < AEC = 5x°, < ADB = 60° and < TAE = x. Find the value of x.
(a)
Curved Surface Area = \(\pi rl\)
\(115.5 = \frac{22}{7} \times r \times 10.5\)
\(115.5 = 33r\)
\(r = \frac{115.5}{33} = 3.5 cm\)
(b)
\(\therefore h^{2} + (3.50)^{2} = (10.5)^{2}\)
\(h^{2} = 10.5^{2} - 3.5^{2}\)
\(h^{2} = 98 \implies h = \sqrt{98}\)
\(h = 9.8994 cm \approxeq 9.90 cm\)
(c) Volume of a cone = \(\frac{1}{3} \pi r^{2} h\)
= \(\frac{1}{3} \times \frac{22}{7} \times \frac{7}{2} \times \frac{7}{2} \times 9.90\)
= \(\frac{23.1 \times 11}{2}\)
= \(127.05 cm^{3} \approxeq 127 cm^{3}\)
Two fair die are thrown. M is the event described by "The sum of the scores is 10" and N is the event described by "The difference between the scores is 3".
(a) Write out the elements of M and N.
(b) Find the probability of M or N.
(c) Are M and N mutually exclusive? Give reasons.
(a) The scale of a map is 1 : 20,000. Calculate the area, in square centimetres, on the map of a forest reserve which covers 85\(km^{2}\).
(b) A rectangular playing field is 18m wide. It is surrounded by a path 6m wide such that its area is equal to the perimeter of the path. Calculate the length of the field.
(c) The diagram shows a circle centre O. If < POQ = x°, the diameter of the circle is 7 cm and the area of the shaded portion is 27.5\(cm^{2}\). Find, correct to the nearest degree, the value of x. [Take \(\pi = \frac{22}{7}\)].