A community group is planning the expansion of a square flower garden in a city park. If each side of the original garden is increased by 4 meters, the new total area of the garden will be 100 square meters. Find the length of each side of the original garden.
A:4 m
B: 10 m
C: 2 m
D: 6 m
so the new garden is 10x10
x+4 = 10