Problem preview
G-CO.12 Core M1-035-R08-V01

Perform formal constructions with compass/straightedge, paper folding, string, reflective devices, or geometry software.

Copy an angle with compass and straightedge

Problem

Copy angle \(ABC\) at endpoint \(P\) of ray \(PX\). A \(B\)-centered source arc meets the angle rays at \(Q\) and \(R\), and the matching \(P\)-centered target arc meets ray \(PX\) at \(S\). Complete the angle copy by stating the target-arc action, chord transfer and center, target intersection, final ray, and congruence result.

Big Picture

What this problem is really about

Copying an angle means reproducing its geometry, and a radius alone does not record how wide the angle opens. We’ll transfer both the source arc radius and the chord between its ray intersections, then use the matching three lengths to prove that the target central angle matches the source.

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Four variants of this problem type
Curriculum context
Course
Math I
Standard
G-CO.12
Category
Geometry
Domain
Congruence
Objective
Perform formal constructions with compass/straightedge, paper folding, string, reflective devices, or geometry software.
Problem type
Copy an angle with compass and straightedge