We are given a diagram with a triangle and a transversal line intersecting one of its sides. We are given an exterior angle of $84^\circ$ formed by the transversal line and the extended side of the triangle. We need to find the value of the angle $k$. The triangle has two sides marked with the same symbol, which means it is an isosceles triangle. We are also given that two lines are parallel.

GeometryTrianglesIsosceles TriangleParallel LinesAnglesSupplementary AnglesExterior Angle
2025/4/29

1. Problem Description

We are given a diagram with a triangle and a transversal line intersecting one of its sides. We are given an exterior angle of 8484^\circ formed by the transversal line and the extended side of the triangle. We need to find the value of the angle kk. The triangle has two sides marked with the same symbol, which means it is an isosceles triangle. We are also given that two lines are parallel.

2. Solution Steps

First, note that the given exterior angle of 8484^\circ and the angle kk are supplementary angles. Supplementary angles add up to 180180^\circ. Thus,
k+84=180k + 84^\circ = 180^\circ.
From this we get,
k=18084=96k = 180^\circ - 84^\circ = 96^\circ.
Also, since two sides of the triangle are equal, the angles opposite these sides are also equal. Let us call this angle xx. Since the two lines are parallel, the angle inside the triangle adjacent to kk is also xx because these are corresponding angles.
Since we have k=96k=96^\circ, the angle adjacent to kk inside the triangle is 180k=18096=84180^\circ - k = 180^\circ - 96^\circ = 84^\circ. Thus x=84x=84^\circ.
Since the triangle is isosceles with two angles being 8484^\circ, let the third angle be yy.
The sum of the angles in a triangle is 180180^\circ.
x+x+y=180x + x + y = 180^\circ
84+84+y=18084^\circ + 84^\circ + y = 180^\circ
168+y=180168^\circ + y = 180^\circ
y=180168=12y = 180^\circ - 168^\circ = 12^\circ.
The angle kk and the 8484^\circ angle are supplementary, thus we have
k+84=180k + 84^\circ = 180^\circ.
k=18084=96k = 180^\circ - 84^\circ = 96^\circ.

3. Final Answer

k=96k = 96

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