Find the perimeter

Question

hi Tutor,

 

my daugther in 3 grade.  She have a home work problem the question confused us.  Please explain and answer to us.  Thank you.

 

question:

the polygon is made three triangles.  The length of each side of each triangle is 6cm.  What is the perimeter of the polygon?

 

 

Answer 1

Michelle, assuming that the three equilateral triangles form a polygon in the form of a trapezoid, the perimeter would be 30cm. 

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If you can imagine the triangles being lined up in that fashion above, the exposed sides of each triangle would be 6cm long.

 

The top side = 6 cm

The two sides = 6 cm x 2 = 12 cm 

The base of the trapezoid = Two bottom sides of a triangle = 6 cm x 2 = 12 cm

In total for the perimeter, 6 cm + 12 cm + 12 cm = 30 cm 

 

 

Answer 2

The perimeter of a polygon is the distance around the polygon.  This means that you add up all of the exterior sides of that polygon.  When you put the three triangles together with their sides connected, you will obtain a trapezoid no matter how you arrange the triangles.  Since each side of the triangle is 6cm, you will multiply 6 by the number of sides of the polygon formed by those triangles.

Answer 3

This describes three equilateral triangles, each having a side of 6. I assume that the question left out the fact that the triangles share a side with each other, otherwise the question does not give you enough information to answer it. 

So assuming that these triangles have a common side, any way you put these triangles together, you always get the same sized trapezoid ( I wish I could draw a picture for you) and the perimeter of that trapezoid is 30 cm.

 

Hope this helped.