perimeter= 30

5cm
12cm

the lenght of the third side of the triangle is?

What do you think?

mm 13cm??

thats what i gett

You're right!

To find the length of the third side of the triangle, you can use the fact that the perimeter of a triangle is the sum of the lengths of all its sides.

Given that the perimeter is 30, and you already know the lengths of two sides, which are 5cm and 12cm, you can subtract the sum of these two sides from the perimeter to find the length of the third side.

Let's calculate:

Perimeter = 30 cm
Length of first side = 5 cm
Length of second side = 12 cm

Length of third side = Perimeter - (Length of first side + Length of second side)
= 30 cm - (5 cm + 12 cm)
= 30 cm - 17 cm
= 13 cm

Therefore, the length of the third side of the triangle is 13 cm.