In a rhombus, the diagonals bisect each other at right angles. Since you have rhombus
First, note that:
is one of the angles formed by the intersection of diagonal with side .
Since diagonals bisect the angles of the rhombus:
- Triangle
is formed, and angles and are adjacent angles: - Therefore,
as well.
Now, in triangle
- The angle sum property of a triangle states that the sum of the angles is
: Substituting the known angles:
Now, since in rhombus
- Angle
(which is the same as angle ) is .
Thus, the measure of angle