˗ Formed by one pair of bases and one pair of legs.

˗ The bases are always parallel.

˗ The legs are non-parallel sides.

˗ One kind of trapezoid is isosceles trapezoid.

˗ If the diagonals are congruent, then it is an isosceles trapezoid.

˗ The legs of the isosceles trapezoid are always congruent.

˗ The length of mid-segment of trapezoid is 1/2(upper base + under base)

˗ The sum of the consecutive angles is always 180º.

The area is {(upper base + under base)*height}/2 

Kate is in the municipal library. She wants to read a biology book, but she doesn’t know where it is. So, she asks to the librarian, and he says that it is in the middle of the middle section of the library. The construction of the library looks like an isosceles trapezoid and the measures of the bases are 20 m and 40m each and the legs are 30m. If the middle section is the midsegment of the trapezoid and she is on one vertex of the trapezoid now, how many meters she needs to walk?