The measures of two sides of a triangle are 7.3 centimeters and 2.94 centimeters. the triangle's perimeter is 14.8 centimeters. which equation could not be used to find the length of the third side? 1. 7.3 + 2.94 + x = 14.8 2. 14.8 = x + 10.24 3. 14.8 - x = 7.3 + 2.94 4. x - 14.8 = 2.94 + 7.3

The perimeter is 14.8 cm, and this equals the sum of the known two side lengths plus x, the length of the third side:

14.8 cm = (7.3 cm + 2.94 cm) + x
14.8 cm = 10.24 + x
    4.56 cm     = x

#1 is fine.
#2 is fine.
#3 is fine.
#4 makes no sense.  x would come out as larger than the given perimeter, which is not possible.

That they are numbers and related to each other.