If a circle has a diameter of 21 inches, what is the circumference? (Use 22/7 for π.)

66 is the circumference

Step-by-step explanation: Formula of circumference: 2 times pi times R

R is radius and Diameter is 2 times of R. Formula of circumference can also be: pi times R. 22/7 times 21 is 66.

0.16 or 16%

step-by-step explanation:

lets take a coin for example.

if you toss it twice, it has a 1/4 chance of landing on heads both times because 1/2 * 1/2 is 1/4.

with the cards, the chance of picking dog is 0.4. having two people pick one is like picking a card twice in a row. so 0.4 * 0.4 is 0.16, or 16%