Question

Which three lengths could be the lengths of the sides of a triangle?

A. 12 cm, 5 cm, 17 cm

B. 10 cm, 15 cm, 24 cm

C. 9 cm, 22 cm, 11 cm


D. 21 cm, 7 cm, 6 cm

Answer 1

Remember that the sum of the two shorter legs have to be greater than the longest leg.

If they sum to less, they can't even touch.

If they sum to the same, they are on the same line as the long leg, and it is not a triangle.

Answer 2

so b?

Answer 3

Yes.

Answer 4

thanks for your help!

Answer 5

A would just be a line, and C and D could not connect to form a triangle.

Answer 6

No problem. :)

Answer 7

Everyone can be a triangle, scalene triangles.

Answer 8

@vitorfleite No they can't. Draw them out on a piece of paper and you'll see.

Answer 9

I draw a triangle with the lenghts of C, now.

Answer 10

You can't make the 12 and 5 cm lines into a triangle. The only way they can connect is as a straight line.

Answer 11

The two shorter lines cannot connect.

Answer 12

In C and D, the shorter lines don't even add up to the big line.

It's not mathematically possible for two short lines to create a triangle with a long line unless the two short lines sum to greater than the long line.

Answer 13

I understood now, I did wronggg.

Answer 14

No worries. I made the exact same false assumption on here a few months ago. :)