Robert made a design on his wall with the similar pentagon tiles shown.
L
9 cm
9 cm
R
K
M
Q
s
10 cm
15 cm
10 cm
15 cm
т
U
10 cm
not drawn to scale
P
15 cm
N
What is the length of side RS?
A. 3 cm
B. 4 cm
C. 5 cm
D. 6 cm