Q. In △KLM,KM is extended through point M to point N,m∠MKL=(3x+1)∘, m∠LMN=(7x−8)∘, and m∠KLM=(2x+11)∘. What is the value of x ?Answer:
Understand angles relationship: Understand the relationship between the angles in the problem.The sum of the angles in triangle KLM and the exterior angle at M (angle LMN) must be equal to the straight line angle at M, which is 180 degrees.
Set up equation: Set up the equation based on the angle sum property and the exterior angle theorem.The exterior angle theorem states that the measure of an exterior angle (angle LMN) is equal to the sum of the measures of the two non-adjacent interior angles (angles MKL and KLM).So, we have:m/MKL+m/KLM=m/LMNSubstitute the given expressions:(3x+1)+(2x+11)=(7x−8)
Combine terms and solve: Combine like terms and solve for x. (3x+1)+(2x+11)=(7x−8) 3x+2x+1+11=7x−8 5x+12=7x−8
Move x and constant terms: Move the x terms to one side and the constant terms to the other side.5x+12−5x=7x−8−5x12=2x−8
Isolate x value: Isolate x by adding 8 to both sides of the equation.12+8=2x−8+820=2x
Divide to find x: Divide both sides by 2 to find the value of x.220=22x10=x
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