IKMC 2023 - Grades 9-10 - Set 2 - Self-study Question 15

Question 15

Pentagon ABCDE is split into four triangles of equal perimeter. ABC is equilateral; AEF, DFE and CDF are congruent isosceles triangles. What is the ratio of the pentagon’s perimeter to the perimeter of ABC?

Question illustration

$2/1$
$3/2$
$4/3$
$5/3$
$5/2$