Angles of a Quadrilateral

Part of the Polygons & Quadrilaterals section of Coddy's Geometry journey. Lesson 1 of 59.

A square has four corners of 90°, and $4\cdot 90^{\circ} = 360^{\circ}$ . Now push one corner in, toward the middle. The shape is no longer a square, and that corner's angle gets bigger.

Does the total get bigger too?

$A square with four right angles, and a lopsided four-sided shape with one corner pushed in$

Challenge

Corner C points out, so its angle is small. Push C in until the angle at C is exactly 90°. Watch all four angles and their total while you drag.

Then press Check.

Try it yourself

$Drag the figure and watch$

Drag the figure and watch

All lessons in Polygons & Quadrilaterals

1Polygons

Angles of a QuadrilateralAngles in Any Polygon How Many Sides?Polygon Angles with x Recap: Polygon Angles

4Parallelograms

Parallelograms Neighbouring Angles Opposite Angles Parallelograms with x A Diagonal Inside Recap: Parallelograms

7On Squared Paper

Make a Parallelogram Draw a Tilted Rectangle Draw a Rhombus Draw a Trapezoid and Kite Recap: Squared Paper

10Composite Shapes

Shapes Made of Parts Rectangle and Triangle Area by Subtracting Enough to Find It?Recap: Composite Shapes

2Regular Polygons

Regular Polygons Inside a Regular Polygon Recap: Regular Polygons

5Rectangles, Rhombi, Squares

Rectangles The Diagonal of a Rectangle Rhombus Angles Squares Recap: Special Parallelograms

8Area of Parallelograms

Area of a Rectangle A Side from the Area Slide the Top Area of a Parallelogram Recap: Parallelogram Area

11Polygon Chases

Parallel Sides in a Pentagon Marks, Not Looks Pentagon with x Regular Shapes Together Recap: Polygon Chases