Q. In △PQR,PR is extended through point R to point S,m∠RPQ=(3x+15)∘, m∠PQR=(2x−9)∘, and m∠QRS=(7x−12)∘. Find m∠RPQ.Answer:
Write Equation: To solve for the measure of angle RPQ, we need to use the fact that the sum of the measures of the angles in a straight line is 180 degrees. This means that the sum of the measures of angles PQR and QRS must equal 180 degrees.
Combine Like Terms: First, let's write the equation that represents the sum of the measures of angles PQR and QRS:m∠PQR+m∠QRS=180∘Substitute the given expressions for m∠PQR and m∠QRS:(2x−9)∘+(7x−12)∘=180∘
Isolate Terms with x: Combine like terms to solve for x:2x−9+7x−12=1809x−21=180
Solve for x: Add 21 to both sides of the equation to isolate the terms with x:9x−21+21=180+219x=201
Substitute x into Expression: Divide both sides by 9 to solve for x:99x=9201x=22.33 (repeating)
Recalculate Measure of Angle: Now that we have the value of x, we can find the measure of angle RPQ by substituting x back into the expression for m∠RPQ:m∠RPQ=(3x+15)∘m∠RPQ=(3(22.33)+15)∘m∠RPQ=(66.99+15)∘m∠RPQ=81.99∘ (repeating)
Identify Mistake: However, we have made a mistake. The measure of an angle should be a whole number, and we cannot have a repeating decimal for the measure of an angle. We need to recheck our calculations.
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