algebra
posted by Sella on .
The velocity of a blood corpuscle in a vessel depends on how far the corpuscle is from the center of the vessel. Let R be the constant radius of the vessel; Vm, the constant maximum velocity of the corpuscle; r, the distance from the center to a particular blood corpuscle (variable); and Vr, the velocity of that corpuscle. The velocity Vr is related to the distance r by the equation Vr=Vm (1r^2 /R^2). Find r when Vr=1/4Vm.

Vr = Vm * ( 1  r ^ 2 / R ^ 2 )
Vr = ( 1 / 4 ) Vm
( 1  r ^ 2 / R ^ 2 ) = 1 / 4 Multiply both sides by 4
4 * ( 1  r ^ 2 / R ^ 2 )= 1
4  4 * r ^ 2 / R ^ 2 = 1 Subtract 4 to both sides
4  4 * r ^ 2 / R ^ 2  4 = 1  4
 4 * r ^ 2 / R ^ 2 =  3 Multiply both sides by  1
4 * r ^ 2 / R ^ 2 = 3 Multiply both sides by R ^ 2
4 * r ^ 2 = 3 * R ^ 2 Divide both sides by 4
r ^ 2 = 3 R ^ 2 / 4
r = sqrt ( 3 R ^ 2 / 4 )
r = sqrt ( 3 ) * R / 2