The quadrilaterals have four pairs of congruent corresponding angles so the figures are similar

45°

Step-by-step explanation:

The measure of a base angle of an isosceles right triangle is 45 degrees. In any triangle, the measure of all three angles equals 180 degrees

In rt angle triangle,

One angle is 90 deg.

other 2 angles are equal (Angles Opp. to equal sides)

90°+45°+45°=180° (Angle sum property of triangle)

so other 2 angles are 45° each. (Base angles)

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