Q. In △BCD,m∠B=(8x+12)∘,m∠C=(3x−17)∘, and m∠D=(x+17)∘. Find m∠D.Answer:
Recognize Triangle Angle Sum: Recognize that the sum of the angles in any triangle is 180 degrees.
Write Equation for Triangle BCD: Write an equation that represents the sum of the angles in triangle BCD.m/_B+m/_C+m/_D=180 degrees(8x+12)+(3x−17)+(x+17)=180
Combine Like Terms: Combine like terms in the equation.8x+12+3x−17+x+17=1808x+3x+x+12−17+17=18012x+12=180
Isolate Terms with x: Subtract 12 from both sides of the equation to isolate the terms with x.12x+12−12=180−1212x=168
Solve for x: Divide both sides of the equation by 12 to solve for x.1212x=12168x=14
Find Measure of Angle D: Substitute the value of x back into the expression for m/_D to find its measure.m/_D=(x+17)m/_D=(14+17)m/_D=31 degrees
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