Question

y varies directly as the square of R. If y = 256 when R = 8, find y when R = 6.

Answer 1

Y = K R^2 or K = Y/R^2
Becasuse y =256 when R=8 means that K = 256/64 =4
so
Y = 4R^2
Y = 4(6)^2 = 4*36 =144 when R=6