## Algebra 1

$9x^2(4\pi-1)$
The area of the yellow part is the total area of the circle reduced by the area taken up by red square. The area of the circle is $\pi r^2=\pi(6x)^2=36\pi x^2$ The total area of the red square is $l\times w=3x\times3x=9x^2$ The area of the yellow part is the total area of the circle reduced by the area taken up by red square. $36\pi x^2-9x^2$ Find the greatest common factor of the terms. Find the prime factors of each term. Multiply the common factors to find the GCF. $36\pi x^2=\underline3\times\underline3\times4\times\pi \times\underline x\times\underline x$ $9x^2=\underline3\times\underline3\times\underline x\times\underline x$ GCF$=3\times3\times x\times x=9x^2$ Factor the GCF out of each term. Use the factors that were not part of the GCF. $36\pi x^2-9x^2=9x^2(4\pi-1)$