How many of the following properties are properties of an isosceles trapezoid?
1) In an isosceles trapezoid, two diagonals are equal and intersect at the midpoint of each.
2) In an isosceles trapezoid, two diagonals are equal.
3) In an isosceles trapezoid, two angles adjacent to a base are congruent.
4) In an isosceles trapezoid, two pairs of opposite sides are parallel.