Answer:
EF ≥ 4
Explanation:
EF is the midline of the trapezoid so its length is the average of the two base lengths:
(AD +BC)/2 = EF
AD +BC = 2·EF . . . . multiply by 2
8 +2x -4 = 2(x+2) . . . substitute the expressions for the segment lengths
2x +4 = 2x +4 . . . . . . true for any value of x
We only require that segment BC is non-negative in length, so ...
BC ≥ 0
2x -4 ≥ 0 . . . . substitute the expression for BC
x -2 ≥ 0 . . . . . divide by 2
x ≥ 2
Then segment EF will be ...
x +2 ≥ 4 . . . . add 2 to both sides of the inequality for x
The only restriction the figure puts on the length of EF is ...
EF ≥ 4
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We suggest you talk to your teacher about this problem. The figure shown does not require that EF have any particular value.