WAEC - Mathematics (1991 - No. 24)
Two towns, P and Q, are on (4oN 40oW) and (4oN
20oE) respectively. What is the distance between
them, along their line of latitude? (Give your
answer in teems of π and R, the radius of the earth).
20oE) respectively. What is the distance between
them, along their line of latitude? (Give your
answer in teems of π and R, the radius of the earth).
2πR cos4o
πR sin40o
πR2
cos4oπR3
cos4oπR6
cos4oForklaring
Angular distance = 40o + 20o = 60o
using θ/360 x 2πr for distance between p and Q
= 60/360 x 2πRcos4o = 1/3πRcos4o
using θ/360 x 2πr for distance between p and Q
= 60/360 x 2πRcos4o = 1/3πRcos4o