An equilateral triangle of side length 10 is completely filled in by non-overlapping equilateral triangles of side length 1 . How many small triangles are required?
Answer Choices
A. 10
B. 25
C. 100
D. 250
E. 1000
An equilateral triangle of side length 10 is completely filled in by non-overlapping equilateral triangles of side length 1 . How many small triangles are required?
Answer Choices
A. 10
B. 25
C. 100
D. 250
E. 1000