The Missing Angle
Part of the Angles section of Coddy's Geometry journey. Lesson 23 of 62.
Figures do not always print every number. A corner square silently contributes 90°: the promise it makes is exact, so it joins the sum like any printed measure.
Reading the figure: the square says 90, the label says 130, and the turn demands 360. So y + (90 + 130) = 360, the numbers gather into 220, and y = 140. Unprinted is not unknown: marks carry numbers too.
Challenge
EasyThree angles share the point: a right angle, 145° and x°.
Find x.
Try it yourself
x + (90 + 145) = 360
Solve for x
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