Math
posted by Cindy on .
A pentagon is formed by putting together three identical equilateral triangles and one larger equilateral triangle with length of edge equal to 2 times that of the smaller equilateral triangle. If the perimeter of the smaller triangle is 42 cm, what is the perimeter of the pentagon?
i need help setting up an equation for this problem
let each side of the smaller triangles be x
then the length of the larger triangle is 2x
place 2 of the smaller triangles along a side of the larger, the third of the smaller fits between the two other small ones.
"If the perimeter of the smaller triangle is 42 cm" > 3x=42 so
x=14
now "walk" around the perimeter of the pentagon, I see x+x+x+2x+2x
do you follow that?

The two figures are similar find the ratios (A toB) of the perimeter