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Recap: The Third Side

Part of the Triangles section of Coddy's Geometry journey. Lesson 11 of 63.

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Challenge

Two sides of a triangle are 14 and 8, and the third side is 2x + 2. On the blank sheet, write the range the third side must lie in, then solve it for x and press Check.

Start the lesson to read it in the interactive player and track your progress.

All lessons in Triangles

1Sides and Names

Three Sides, Three CornersSorting by SidesNaming by AnglesTicks into EquationsThe Longest SideRecap: Sorting Triangles

4Area of a Triangle

Half the RectangleHeight Is Not a SideRight Triangle AreaFinding the HeightAny Side Can Be the BaseRecap: Area

7Is It Right?

The ConverseTesting a TriangleAcute or Obtuse?Sorting by the TestRecap: Right or Not

10Scale in the World

ShadowsAcross the RiverNested TrianglesA Side with an ExpressionRecap: Scale in the World

2The Triangle Inequality

Can Three Sticks Meet?Exactly ReachingThe Range of the Third SideThe FormulaRecap: The Third Side

5The Pythagorean Theorem

Squares on the SidesFinding the HypotenusePythagorean TriplesWhen It Is Not WholeRecap: The Hypotenuse

8Special Right Triangles

The 45-45-90 TriangleLegs from the HypotenuseThe 30-60-90 TriangleAll Three SidesWhich Triangle Is It?Recap: Special Triangles

11Two Tools at Once

Height of an IsoscelesArea from the HeightThe Equilateral TriangleRight Triangle PerimeterRecap: Two Tools

3Perimeter

Around the EdgeA Missing SideIsosceles PerimeterSides as ExpressionsRecap: Around the Edge

6Finding a Leg

Working BackwardsThe LadderWhich Side Is c?A Leg That Is Not WholeRecap: Finding a Leg

9Similar Triangles

Same Shape, Different SizeThe Scale FactorFinding a SideMatching the CornersRecap: Similar Triangles

12Final Challenges

Final: Three SticksFinal: The FenceFinal: The LadderFinal: The ShadowFinal: Master of Triangles