Complete the following:
(a) A quadrilateral has ____________ sides.
(b) A quadrilateral has ____________ diagonals.
(c) A quadrilateral in which one pair of sides are parallel to each other is ____________.
(d) In an isosceles trapezium, the base angles are ____________.
(e) In a rhombus, the diagonals bisect each other in ____________ angles.
(f) In a square, all the sides are ____________.
A field is in the shape of an isosceles trapezium with parallel sides measuring 20 m and 8m and its non-parallel sides measuring 10 m. Find its area ___ (in cm2).