Solve the Problem $1.6 \mathrm { sec }$ For A $0.64 \mathrm {~m}$

Solve the problem.
-The period of a pendulum is the length of time required to complete one swing back and forth. The period varies directly as the square root of the length of the pendulum. If it takes $1.6 \mathrm { sec }$ for a $0.64 \mathrm {~m}$ pendulum to complete one period, what is the period of a $1.21 \mathrm {~m}$ pendulum?

A) $2.6 \mathrm { sec }$
B) $3 \mathrm { sec }$
C) $2.2 \mathrm { sec }$
D) $0.5 \mathrm { sec }$