#How do I solve these with steps
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$\angle{A},\angle{B},\angle{C},\angle{D}$ are inscribed angles, meaning that their measures are equal to half the measures of their intercepted arcs.
For example,
$\newline\angle{A}=\frac{1}{2}\cdot\overset{\huge\frown}{BD}$
solarunes
so basically, opposite angles in an inscribed quadrilateral of a circle are supplementary
so angle D is 115 degrees
Also, inscribed angle measures are half of their intercepted arc measures
so if arc BC is 65 degrees and arc CD is 149 degrees, we add them up
and get 214 degrees
half that, and we have 107 degrees for angle A
angle C is supplementary to A, so it is 73 degrees
For the second one, we know that if a radius is perpendicular to a chord, then it bisects the chord into congruent segments
so the right triangle has measures x, 10.9, and 12.6
we can use pythagorean theorem to find x
(12.6)^2-(10.9)^2=x^2, or 39.95
square root both sides, and you get x is about 6.3206012372241930573281107524048