Robin has to go shopping for her brother's birthday.
She already bought "x" presents for him.
The next day, Robin bought "2" more presents for him just in time for his birthday.
When she got home and celebrated his birthday, her beother opened, in total, "9" presents.
--- What is the number of presents that Robin had originally purchased? ---
Hey, I'll be happy to assist you, but I need a picture or diagram with the measurements of the polygon and the poly itself :)
Octogon
sides=4
draw lines from the outside angles to the center so they form 8 equal triangle sections
find the area of each triangle and multiply by 8
area of triangle=1/2 base times height
base=4
the height is the distance from the center of one side of the octogon, to the center=5
so area=4 times 1/2 times 5=4 times 5=10
8 triangles so 8 times 10=80
the answer is 80cm^2
the diagram included below shows area for a pentagon