JAMB - Mathematics (1987 - No. 36)
Taking the period of day light on a certain day to be from 5.30a.m to 7.00p.m. Calculate the angle of a pie chart designed to show the periods of the day light and of darkness on that day
187o30'
172o30'
135o225o
202o30' 157o 30'
설명
Period of day light is from 5.30 to 7.00p.m - 13hrs 30min. interval
24hrs make 1 day
∴ period of darkness = 24hrs - 13hrs 30mins = 10hrs 30mins.
Angle of sector of daylight = \(\frac{13 \times 60 + 30 \times 360}{(24 \times 60)}\)
= \(\frac{810}{1440}\) x 360o
= \(\frac{291600}{1440}\)
= 202.5o
202.5o = 202.30o
darkness period = 360o - 202o 30'
= 157o30'
= 202o30' 157o 30'
24hrs make 1 day
∴ period of darkness = 24hrs - 13hrs 30mins = 10hrs 30mins.
Angle of sector of daylight = \(\frac{13 \times 60 + 30 \times 360}{(24 \times 60)}\)
= \(\frac{810}{1440}\) x 360o
= \(\frac{291600}{1440}\)
= 202.5o
202.5o = 202.30o
darkness period = 360o - 202o 30'
= 157o30'
= 202o30' 157o 30'