Triangles ABC and DEF are equal and both are isosceles. Find the perimeter of triangle ABC if DE = 4 cm EF = 5 cm.

Consider the first option, when AC = CB, DF = EF, then the perimeter of the triangle DEF will be equal to:

Pdef = DE + EF + DF = 4 + 5 + 5 = 14 cm.

Since equal triangles have equal perimeters, then Ravs = 14 cm.

Consider the first option, when AC = AB, DF = ED, then the perimeter of the triangle DEF will be equal to:

Pdef = DE + EF + DF = 4 + 5 + 4 = 13 cm.

Since equal triangles have equal perimeters, Ravs = 13 cm.

Answer: The perimeter of triangle ABC is 14 cm or 13 cm.



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