To find the missing length, we need to add up the lengths of the three sides of the triangle and then find the missing length by subtracting the sum of the other two sides from the perimeter.
Let the three sides of the triangle be A, B, and C. The perimeter is the sum of the lengths of the three sides: A + B + C.
Given that the perimeter is 20x-13, we have:
A + B + C = 20x - 13
Let's say the missing length is A. Then we have:
A + 7x - 20 + 13x + 7 = 20x - 13
Combine like terms:
20x - 13 + 7 - 20 = 7x + 13x + A
7x - 6 = 20x - 20 + A
Subtract 20x from both sides:
-13 = -13 + A
A = -13 + 13 = 0
Therefore, the missing length A is 0. There was no need to choose 7 x minus 20, 13 x plus 7, or 13x-7, or 7x-11.
A triangular park is shown below.
If the perimeter of the park is 20x-13
, what is the missing length?
Responses
7 x minus 20
13 x plus 7
13x-7
7x-11
1 answer
1 answer