For quadrilateral ABCD to be a parallelogram, the opposite sides must be equal. This means we need to set the following equations based on the side lengths:
- \( AB = CD \)
- \( BC = AD \)
Substituting the given expressions for side lengths:
- \( 40x = 8x + 32 \)
- \( 4 + 3y = 9y - 20 \)
Let's solve these equations one at a time.
For the first equation: \[ 40x = 8x + 32 \] Subtract \( 8x \) from both sides: \[ 40x - 8x = 32 \] \[ 32x = 32 \] Now divide by 32: \[ x = 1 \]
For the second equation: \[ 4 + 3y = 9y - 20 \] Add \( 20 \) to both sides: \[ 4 + 20 + 3y = 9y \] \[ 24 + 3y = 9y \] Subtract \( 3y \) from both sides: \[ 24 = 9y - 3y \] \[ 24 = 6y \] Now divide by 6: \[ y = 4 \]
So, we have found \( x = 1 \) and \( y = 4 \).
Thus, Erik can be sure that his quadrilateral is a parallelogram for the values \( x = 1 \) and \( y = 4 \).
The correct response is: x equals 1 and y equals 4.