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2019 AMC 10B Problem 5

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2019 AMC 10B Problem 5AMC 10 Step by Step

Name: Date: September 13, 2026

Coordinate Geometry · difficulty 1 of 5 · about 2 min · position P1-10

Triangle $ABC$ lies in the first quadrant. Points $A$ , $B$ , and $C$ are reflected across the line $y=x$ to points $A'$ , $B'$ , and $C'$ , respectively. Assume that none of the vertices of the triangle lie on the line $y=x$ . Which of the following statements is not always true?

A)
Triangle $A'B'C'$ lies in the first quadrant.
B)
Triangles $ABC$ and $A'B'C'$ have the same area.
C)
The slope of line $AA'$ is $-1$ .
D)
The slopes of lines $AA'$ and $CC'$ are the same.
E)
Lines $AB$ and $A'B'$ are perpendicular to each other.

2019 AMC 10B Problem 5

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