JH0518611IN JH0518611IN Mathematics Answered Do the base angles in an isosceles right triangle always measure 45°45°? a.) Yes, the base angles of any isosceles triangle are congruent and supplementary, so their measures must be 45°45°. b.) yes, the base angles of a right isosceles triangle are congruent and complementary, so their measures must be (fraction) 90°/2 = 45° c.) No, the base angles of a right isosceles triangle are not always congruent. d.) No, the base angles of a right isosceles triangle are congruent, but they can both equal 90°90°.