Since 7 coins is only 5% of the entire collection, 7 coins=5%. 100% is the total. So first you need to divide 100 by 5 which is 20 (100÷5=20). Next, you need to multiply 20 by 7 (20×7=140) to find out how much coins she has in total.
<span>On the one hand we know that sin(30) = 1/2. On the other hand we know that sin(A) = a/c. From these two relations we obtain that 1/2 = a/c <=> 1/2 = a/12 <=> a = 12*1/2 <=> a = 6. So the answer is D. 6cm.</span>
