A circular track has a radius of 21 m. Find its circumference. (Use pi = 22/7.)

Step 1: Identify the given values

The problem provides the radius of the circular track, $r = 21$ meters, and specifies that we should use the approximation $\pi = \frac{22}{7}$ for the value of pi.

Step 2: Recall the formula for circumference

The circumference of a circle is the distance around its edge. The formula to calculate the circumference ($C$) of a circle with radius ($r$) is $C = 2\pi r$.

Step 3: Substitute the values into the formula

Now, we substitute the given values of the radius ($r = 21$) and $\pi = \frac{22}{7}$ into the circumference formula.

Step 4: Calculate the circumference

Perform the multiplication. First, simplify by dividing 21 by 7, which gives 3. Then multiply $2 \times 22 \times 3$ to get the final circumference.

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