Question

the inside perimeter of a running track ,as shown in figure is 340 m .,....​

Answer 1

Answer:

answers are 384m and 2534m²

Step-by-step explanation:

Inside perimeter = 2(perimeter of semicircles + length of the track)

340m = 2(πr+60)m

(πr+60)m = 340/2 = 170

πr = 170-60 = 110

r = (110×7)/22 (when π = 22/7)

= 5×7 = 35m

As the width of track is 7m

so radius of outer circle will be = 35m+7m = 42m

Perimeter of outer track = 2(perimeter of outer semicircles + length of the track)

Perimeter of outer track = 2(πr + 60)m

= 2{(22×42)/7)+60]m

= 2[(22×6)+60]m

= 2(132+60)m

= 2× 192m

= 384m

Area of track = 2(area of semicircles) + area( rectangle) - (area of inner track)

= 2[(πr²/2]+ (lb)- (πr²+lb)

= πr²+lb - πr²+lb

= 22/7(42)²+ 60(42+42) -22/7(35)²+ 60(70)

= 22(6)(42) + 60(84)-22(5) (35) +4200

= 10584m²- 8050m²

= 2534m²