What is the Midsegment theorem of a trapezoid?

The midsegment of a trapezoid calculator, allows you to obtain the length of the midsegment or median of a trapezoid. The median of a trapezoid is a line parallel to the bases placed in the midpoint between them. With this tool, you will learn the midsegment of a trapezoid formula and how to find the midsegment of any trapezoid.

The median or midsegment of a trapezoid is a line parallel to the trapezoid's bases, which crosses the midpoint between them. It extends from one non-parallel side to the other.

A trapezoid with abcd sides.

Given the length of one base, you can use the midsegment to find the length of the other. Let's take a look at the midsegment of a trapezoid formula to learn how.

The median or midsegment of an ABCD trapezoid formula is straightforward. We just need the length of each of the bases (ABABAB and CDCDCD), add them, and then divide the result by two:

Midsegment=AB+CD2\text{Midsegment} = \frac{AB+CD}{2}Midsegment=2AB+CD​

This is the same as finding the median or average value between the bases, hence the name. If you find any two variables, you can obtain the other with ease by replacing the values in the equation above, or simply use the midsegment of a trapezoid calculator, and it will do the work for you 😉.

To find the midsegment of a trapezoid:

  1. Measure and write down the length of the two parallel bases.
  2. Add the two numbers.
  3. Divide the result by two. This is the length of the midsegment.

You can verify the result with the midsegment of a trapezoid calculator or take a look at our trapezoid calculator to learn more.

A trapezoid has only one midsegment. The midsegment is a line that extends from one non-parallel side to the other, is parallel to the bases, and is placed at the midpoint between them.

The midsegment of a trapezoid with 2 cm bases is 2 cm. The formula for the midsegment is (AB + CD) / 2, and since AB and CD are identical, the result and the bases' lengths are equal in number.

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The midsegment of a trapezoid is parallel to each base, and its measure is half the sum of the lengths of the bases.

What is the Midsegment theorem of a trapezoid?

The following relation holds true for midsegment FE.

FE∥AB∥DC and FE=21​(AB+CD)

Let ABCD be a trapezoid and FE be its midsegment. By definition, the midsegment of a trapezoid connects the midpoints of the nonparallel sides.

What is the Midsegment theorem of a trapezoid?

Next, draw the line connecting the points C and F, then extend the base AB such that it intersects with CF. Let G be the point of intersection between these two lines.

What is the Midsegment theorem of a trapezoid?

By the Vertical Angles Theorem, it is given that ∠AFG and ∠CFD are congruent angles. Also, since GB and CD are parallel, then ∠GAF and ∠D are congruent angles by the Alternate Interior Angles Theorem.

What is the Midsegment theorem of a trapezoid?

Triangles GAF and CDF have two pairs of congruent angles and a pair of included congruent sides. Therefore, by the ASA Congruence Theorem, it is concluded that △GAF≅△CDF. Since corresponding parts of congruent figures are congruent, then GA≅CD and FG≅FC. Since FG and FC are congruent, it can be stated that F is the midpoint of CG, and it is given that E is the midpoint of CB. Consequently, FE is a midsegment of △GBC. Therefore, by the Triangle Midsegment Theorem, FE and GB are parallel and FE is half GB. Using the fact that FE and GB are parallel, the first part of the theorem can be obtained.

What is the Midsegment theorem of a trapezoid?

To obtain the second part, rewrite GB using the Segment Addition Postulate. Since GA≅CD, then GA=CD. Finally, substituting the equation above into the equation given by the Triangle Midsegment Theorem, the desired result will be obtained.

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