The formula for area of a circle is (pi)*radius^2
Radius is half of diameter so the radius is 2.
2 squared is 4, then multiply by pi to get an answer of 4(pi) or 12.56.
15 cards = 9$
1 card = (9/15)$
12 cards = 9/15 * 12
= 108/15
= 7.2$
Answer:
1. Not accounting for the difference in the base of the exponent when applying the quotient rule.
2. Not subtracting the exponents of the denominator from the exponent of the numerator when applying the quotient rule.