Trapezoid area with sides 7.14,3.5,1.8,2.71 equal to 6.857
where a and b are bases, h is height
where m is the middle line, h is the height
where d1,d2 are diagonals, α° is the angle between them
A trapezoid is a quadrilateral whose two sides are parallel (bases) and the other two are not parallel (sides).
Trapezoid area formula 
where a and b are the bases, c and d are the sides
where r is the radius of the inscribed circle, α° is the angle between the base and the sideSolution:
S =
a+b
2
·
√c2 - ()2
(b-a)2+c2-d2
2·(b-a)
=
7.14+3.5
2
·
√1.82 - ()2
(3.5-7.14)2+1.82-2.712
2·(3.5-7.14)
=
10.64
2
·
√1.82 - ()2
-3.642+1.82-2.712
2·-3.64
=
10.64
2
·
√3.24 - ()2
13.2496+3.24-7.3441
-7.28
= 5.32
·
√3.24 - ()2
9.1455
-7.28
= 5.32
·
√3.24 - -1.2562
= 5.32
·
√3.24 - 1.577536
= 5.32
·
√1.662464
= 5.32
·
1.289
=
6.857
Answer: trapezoid area with sides 7.14,3.5,1.8,2.71 equal to 6.857