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AB and CD are parallel straight lines and HI is the transversal intersecting AB at E and CD at F. G is a point between the lines AB and CD but not on HI, such that m\angle EGF=65°. If 52×m\angle BEG=53×m\angle DFG, and m\angle DFG=31×m\angle DFE, what is the measure of ∠FEG?
Not enough information
Dependent on the location of G
A specific numerical value
Cannot be determined
A specific numerical value
Use the ratio m∠DFG = (1/3)m∠DFE to find m∠EFG = 2/3 m∠DFE. Since AB||CD, alternate interior angles imply ∠BEF = ∠DFE. Solve the linear system for angles at E and F.
AB || CD, transversal HI intersects at E and F. G is between lines. m∠EGF = 65°, (2/5)m∠BEG = (3/5)m∠DFG, m∠DFG = (1/3)m∠DFE.
Ext. Angle Property: ∠EGF=∠FEG+∠EFG
Use the ratio m∠DFG = (1/3)m∠DFE to find m∠EFG = 2/3 m∠DFE. Since AB||CD, alternate interior angles imply ∠BEF = ∠DFE. Solve the linear system for angles at E and F.
Confusing transversal segments; remember that the angle at G is the exterior angle of triangle EFG formed by the lines from E and F to G.
Establish Relationships
Let x=∠BEG and y=∠DFG. Given 52x=53y, so x=1.5y. Also ∠DFG=31∠DFE, so ∠DFE=3y.
x=1.5y,\angle DFE=3y
Relate Interior Angles
Since AB∥CD, ∠BEF=∠DFE=3y (alternate interior). ∠FEG=∠BEF−∠BEG=3y−1.5y=1.5y.
∠FEG=1.5y
Calculate using Triangle Property
In △EFG, the exterior angle ∠EGF=65°=∠FEG+∠EFG. Since ∠EFG=∠DFE−∠DFG is not necessarily simple, we use the property ∠FEG+∠EFG=65°. Substituting 1.5y+(3y−y)=65°→3.5y=65°. Solving for y and calculating ∠FEG=1.5y gives 63°.
∠FEG=63°
C is correct because the geometric constraints and angle relationships satisfy the sum of interior angles in the triangle yielding 63°.
Always identify the alternate interior angles first in parallel line problems to reduce the number of variables.