Question

Hiep is writing a coordinate proof to show that the midsegment of a trapezoid is parallel to its bases. He starts by assigning coordinates as given, where RS¯¯¯¯¯ is the midsegment of trapezoid KLMN. Trapezoid K L M N on the coordinate plane. The vertices of the trapezoid are K begin ordered pair 0 commas 0 ends ordered pair, L begins ordered pair 2a comma 0 end ordered pair, M begin ordered pair 2d comma 2c end ordered pair, and N begin ordered pair 2b comma 2c end ordered pair. Segment R S is drawn with point R on segment K N and point S on segment L M. Drag and drop the correct answers to complete the proof. Since RS¯¯¯¯¯ is the midsegment of trapezoid KLMN, the coordinates of R are (b, Response area) and the coordinates of S are (, c). The slope of KL¯¯¯¯¯ is the Response area. The slope of RS¯¯¯¯¯is 0. The slope of NM¯¯¯¯¯¯¯ is 0. The slope of each segment is 0; therefore, the midsegment is parallel to the bases. choices - a, b,c,d a+d, 0, 1, 2

Answer 1

Step-by-step explanation:

boy, that is hard to decipher ...

but from what I understood after a while of reading and re-reading, the proof is based on the equal slope (0) of all 3 lines showing that all 3 lines are parallel.

remember, the slope is the ratio y/x indicating how many units y changes, when x changes a certain amount of units when going from one point to another.

so, going from N to M :

x changes by (2d - 2b) units.

y changes by 0 units (2c to 2c).

so, the slope of NM is 0/(2d - 2b) = 0.

going from K to L :

x changes by (2a - 0) = 2a units.

y changes by 0 units (0 to 0).

so, the slope of KL is 0/2a = 0.

R and S are the middle points between K and N, and between L and M.

R = ((2b+0)/2, (2c+0)/2) = (b, c)

S = ((2d + 2a)/2, (2c + 0)/2) = ((d+a), c)

so, going from R to S :

x changes by (d+a-b) units.

y changes by 0 units (c to c).

so, the slope of KL is 0/(d+a-b) = 0.

as all 3 slopes are equal (and with being 0 also parallel to the x-axis), this proves that the line RS is parallel to its bases.