Respuesta :

We divide the total set into several sub-sets (subgroups) that contain the exact same number of members. This way we know the number of total members by adding the number of total subsets.

Answer:

Draw 20 equilateral triangles such that 5 triangles having sides measure 4 cm , 7 triangles have sides measure 7 cm , 3 triangles have side 10 cm and rest of the triangles have side of measure 5 cm.

This will become a set of equilateral triangles .

Let consider a subgroup set of the original set of having equilateral triangle with side-length of 5 cm.

Then the number of triangle having side-length 5 cm= 20-5-7-3=5

Now, the fraction of the group having triangle with side- length 5 cm is given  by:-

[tex]\frac{\text{triangle having side-length 5 cm}}{\text{total triangle}}=\frac{5}{20}=\frac{1}{4}[/tex]