Chapter 12.7, Problem 4OE

To determine

Area A of the surface of a steel ball is directly proportional to the square of the diameter d of the ball, use k as a constant where needed.

Answer to Problem 4OE

  $A=k\cdot d^2$

Explanation of Solution

Given information:

Area A of the surface of the steel ball is directly proportional to the square of the diameter d of the ball.

That is $A\prec d^2$...... $\left(1\right)$

Given k is constant.

Put k as a constant in equation 1 .

  $A=k\cdot d^2$

Thus the formula for statement is $A=k\cdot d^2$ .