Write the Equation
Part of the Angles section of Coddy's Geometry journey. Lesson 10 of 62.
So far the canvas has handed you the equation. Real geometry starts one step earlier: you look at the figure, name the rule it obeys, and write the equation yourself.
Reading this figure: two angles stand together on a straight line, so their measures add to 180°. The angles are (x + 10)° and 130°, and the sentence writes itself: (x + 10) + 130 = 180. Nothing is solved yet, and that is fine. Writing the true sentence is the skill.
Challenge
EasyTwo angles stand together on a straight line: (x + 25)° and 90°.
Write the equation the figure states. Do not solve it.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Angles
1Meet the Angle
Your First AngleNaming AnglesAdding Adjacent AnglesDegrees and the Full TurnAcute, Right, ObtuseRecap: Adjacent Angles4Vertical Angles
Linear PairsVertical Angles Are EqualSolving with VerticalsAll Four AnglesRecap: At the Crossing2Straight Lines and Supplements
Angles on a LineSupplementary AnglesThree Angles on a LineWrite the EquationRecap: Along the Line5Around a Point
Angles Around a PointThe Missing AngleEqual SlicesFour Angles, One PointRecap: The Full Turn3Right Angles and Complements
Complementary AnglesFinding the ComplementPerpendicular LinesEqual Parts of a CornerRecap: The Right Corner6The Angle Bisector
The Angle BisectorBisected ExpressionsBisecting a Straight AngleRecap: Split in Half