Question

the diagram shows a running track with a straight of 100 meter and 2 semi circular ends of diameter 56 meter i) find the cost of plastering the area covered by the track at rs 55 per sq. meter. ii) find the cost of finishing the track at rs 175 per meter

Answer 1

Answer : 

6216m2,488m6216m2,488m

Solution : 

90+90+2πr=400⇒2×227×4r=220⇒r=35m90+90+2πr=400⇒2×227×4r=220⇒r=35m

So, R=(35+14)m=49mR=(35+14)m=49m

Area of the track =[(90×14)+227×{(49)2−(35)2}]m2=6216m2=[(90×14)+227×{(49)2-(35)2}]m2=6216m2

Length of the outer boundary =(90+90+2πR)m=(90+90+2πR)m, where R=49mR=49m

=488m