Answer: x = 29
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Work Shown:
Focus on triangle DEC. We have angle C is 48 and D is 74. Let's find angle E.
D+E+C = 180
74+E+48 = 180
E+122 = 180
E = 180-122
E = 58
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In the sequences ABC and DEC, we have B and E as the second letters. The order is important because the angles must align properly (so we know how they pair up). Therefore, angle B = angle E because triangle ABC = triangle DEC.
Furthermore,
angle B = angle E
2x = 58
x = 58/2
x = 29