There are three 90 degree angles. (Looking at home plate from a "pitcher's viewpoint), the wide "front" of home plate has 90 degree angles on both sides. The back point, e.g. "the heart of the plate," is a 90 degree angle. The two angles closest to the batter's back foot are both 135 degrees. This is because these angles are the sum of a 90 degree angle and a 45 degree angle. The back "triangle" of home plate is a 45-45-90 triangle.
Base angles.
A trapezoid always has two acute angles. the base angles have to be acute because the lower base angles and the upper base angles are complementary so since the upper base angle is always obtuse, the lower base angles have to be acute.
Either of the two angles of a triangle that has the base for a side.
Base Angles
The base angles of an isosceles triangle are congruent.
The base angles of an isosceles trapezoid are congruent
There are two pairs of congruent base angles in an isosceles trapezoid.
The base angles are always congruent.
The base angles of an isosceles triangle are congruent. The vertex angle of an isosceles triangle is not necessarily congruent to the base angles.
The base angels of a trapezoid are the angles that attach to the legs of the trapezoid. There are four base angles in a trapezoid.
They are the basal angles.
They would probably be the two pairs of angles in the parallelogram or kite base of a quadrilateral based.