Q. In △LMN,LN is extended through point N to point O,m∠MNO=(6x−13)∘, m∠NLM=(x+7)∘, and m∠LMN=(2x+4)∘. Find m∠LMN.Answer:
Set Up Equation: To find the measure of angle LMN, we need to use the fact that the sum of the angles in a triangle is 180 degrees. We have the measures of the angles in terms of x, so we can set up an equation to solve for x.
Given Angle Measures: First, let's write down the given angle measures in terms of x: m/_MNO=(6x−13)∘ m/_NLM=(x+7)∘ m/_LMN=(2x+4)∘
Exterior Angle Theorem: Since LN is extended through point N to point O, angle ∠MNO is an exterior angle to triangle LMN. According to the exterior angle theorem, the measure of an exterior angle is equal to the sum of the measures of the two non-adjacent interior angles. Therefore, m∠MNO=m∠NLM+m∠LMN.
Combine Like Terms: Now we can set up the equation based on the exterior angle theorem:(6x−13)∘=(x+7)∘+(2x+4)∘
Solve for x: Combine like terms on the right side of the equation:(6x−13)∘=(3x+11)∘
Isolate Term with x: Now, solve for x by subtracting 3x from both sides:6x−13−3x=3x+11−3x3x−13=11
Substitute x Back: Add 13 to both sides to isolate the term with x:3x−13+13=11+133x=24
Calculate Value: Divide both sides by 3 to solve for x:33x=324x=8
Calculate Value: Divide both sides by 3 to solve for x: 33x=324 x=8Now that we have the value of x, we can find the measure of angle LMN by substituting x back into the expression for m/_LMN: m/_LMN=(2x+4)∘ m/_LMN=(2(8)+4)∘
Calculate Value: Divide both sides by 3 to solve for x: 33x=324 x=8Now that we have the value of x, we can find the measure of angle LMN by substituting x back into the expression for m/_LMN: m/_LMN=(2x+4)∘ m/_LMN=(2(8)+4)∘Calculate the value: m/_LMN=(16+4)∘ m/_LMN=20∘
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