Question

Area of a circular ring: A = 4bsmiddle" class="latex-formula">pw
Solve for p. Find p when A = 22 cm^2 and w = 2 cm

Perimeter of a track: P = 2$\pi$r + 2x
Solve for r. Finf r when P = 440 yrds and x = 110 yrds

Answer 1

1a)      A = 4πpw
      /4πw = /4πw
  A / 4πw = p

1b) A = 4πpw
     22 = 4πp(2)
       p = 11/4π (≈0.87)

2a)        P = 2πr + 2x
      P - 2x = 2πr
        /2π      /2π
 P-2x / 2π = r

2b)    P = 2πr + 2x
      440 = 2πr + 2(110)
          r = 110/π (≈35.014)