Hola User__________
Here is your Answer...!!!
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Actually welcome to the concept of the Angle sum property...
The Angle sum property of a Quadilatetal =》
m/_A + m/_B + m/_C + m/_ D = 360°
Thus adding all the angles we get as....
=》 X + X + X+ 15° + X + 45° = 360°
=》 4X + 60° = 360°
thus ..4X = 360 - 60 = 300
Thus .. 4X = 300
X = 300 ÷ 4 =》 75°
X = 75°
Because base angles are congruent, both angle A and B are congruent. If the two triangles are congruent, then the base angles are the same, meaning 5x=50*. Divide by 10 and you get the answer of x=5. :) Hope this helps!
The answer is 10.2 cm. If you want the work, please say so in the comments below.