To find the greatest common factor (GCF) between monomials, take each monomial and write it's prime factorization. Then, identify the factors common to each monomial and multiply those common factors together. Bam!
First draw the frame around the triangle. The circular edges added together give you 360 degrees. Use pi*r^2 to get 4pi which is around 12.56. 100cm=m. 2*500+2*400*2*700=3200.