The perimeter of a triangle is 29 if two of the sides are 10 & 12 what is the length of the third side

Step-by-step explanation:

The perimeter is equal to the sum of all the sides. Since a triangle has 3 sides and you are only missing one,

P=10+12+x

We have the perimeter, so we can substitute P for 29

29=10+12+x

now we solve for x, the missing side

29=22+x

x=7

The length of the 3rd side is 7 [insert unit here].