General Mathematics Paper 2,Nov/Dec. 2010
 Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 Main
Weakness/Remedies
Strengths
>
Question 12

P(lat 400N, long 18°W) and Q(lat 400N, long 78OW) are two cities on the surface of the earth. Calculate, the:
(a) radius of the parallel of latitude on which P and Q lie, correct to the nearest 10km;
(b) length of the minor arc PQ, correct to the nearest 100 km;
(c) vertical distance between the centre of the earth and the centre of the small circle on which P and Q lie, correct to the nearest km.
[Take π = 22/7 and radius of the earth= 6400 km]

_____________________________________________________________________________________________________
Observation

This question was reportedly attempted by majority of the candidates and their performance was described as fair. Candidates were also reported to have performed better in parts (a) and (b) than in part (c). Majority of the candidates could not find the vertical distance between the centre of the earth and the centre of the small circle on which P and Q lie.
According to the report majority of the candidates did not draw the correct diagram. Others did not draw the diagram at all. Teachers are encouraged to stress the need for drawing appropriate diagrams that will aid the candidate in answering such questions.

Radius of the parallel of latitude on which P and Q lie = R cos 40° = 4902.4 km = 4900km to
the nearest 10 km. Length of minor arc PQ = 60/360- x 2 x 22/7 x 4902.4 = 5100 m to the nearest
100 km. Length of the distance IOXI = R sin40° = 6400 x 0.6428 = 4114km to the nearest km.