If $7 * 24 = 25$ and $12 * 16 = 20$, then what is $16 * 63$ equal to?
If $7 * 24 = 25$ and $12 * 16 = 20$, then what is $16 * 63$ equal to?
70
66
65
64
Solution
The operation $a * b = \sqrt{a^2+b^2}$. Check: $\sqrt{7^2+24^2}=\sqrt{49+576}=\sqrt{625}=25$ and $\sqrt{12^2+16^2}=\sqrt{144+256}=\sqrt{400}=20$. So $16*63 = \sqrt{16^2+63^2}=\sqrt{256+3969}=\sqrt{4225}=65$.