Solve the Problem $\frac { 3 } { 4 }$ Of the Preceeding Swing

Multiple Choice

Solve the problem.
-A pendulum swings a length of 20 centimeters on its first swing. Each successive swing is $\frac { 3 } { 4 }$ of the preceeding swing. Find the length of the fourth swing and the total length swung during the first four swings. Round to the nearest tenth of a centimeter, if necessary.

A) $6.3 \mathrm {~cm} ; 41 \mathrm {~cm}$
B) $11.3 \mathrm {~cm} ; 8.4 \mathrm {~cm}$
C) $11.3 \mathrm {~cm} ; 46.3 \mathrm {~cm}$
D) $8.4 \mathrm {~cm} ; 54.7 \mathrm {~cm}$