What expressions go in the derivation of the tangent sum identity in place of A, B, and C?

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

A. s.a.! similarity in right triangles, refer to the figure to complete this proportionc/a = a/? a.) cb.) hc.) rd.) s

Use the following statements to write a compound statement for the conjunction or disjunction. then find its truth value. p: an isosceles triangle has two congruent sides. q: a right angle measures 90° r: four points are always coplanar. s: a decagon has 12 sides. a) a right angle measures 90° or an isosceles triangle has two congruent sides; true. b) a right angle measures 90° and an isosceles triangle has two congruent sides; true. c) a right angle measures 90° and an isosceles triangle does not have two congruent sides; false. d) a right angle measures 90° or an isosceles triangle does not have two congruent sides; true.