Polygon a closed figure formed by three or

Polygon: a closed figure formed by three or more line segments. Notice, polygons are Circlessince are not polygons. Quadrilateral Pentagon Hexagon Triangle

Triangle: a polygon with three sides Classified by sides and angles

Congruent sides have the same length. You can classify a triangle by the number of congruent sides it has.

Scalene triangle: no congruent sides.

Isosceles triangle: at least two congruent sides. Tick marks are used to indicate congruent sides

Equilateral triangle: three congruent sides. All equilateral triangles are also isosceles triangles.

You can also classify a triangle by its angle measures.

Right triangle: one right angle A square indicates the 90° angle in the right triangle.

Acute triangle: three acute angles (angles of less than 90°)

Obtuse triangle: One obtuse angle (angle greater than 90°)

Quadrilateral: a polygon with four sides Parallelogram: a quadrilateral with both pairs of opposite sides parallel.

Rectangle: a parallelogram with four right angles Square: a rectangle with four congruent sides

What is the area of this rectangle?

H E I G H T B A S E Length x Width or Base x Height

H E I G H T Correct 48 square units B A S E So how big is this rectangle?

Then move A parallelogram If, with the help of th President, it to 16 the is formed our which side… hasother the we chop same aarea piece asoff thethe rectangle…

And since it has the same area, base x height we can use the same formula. Always look for the 90° square.

Don’t worry about the length of the sides. That is called “slant height. ”

Sometimes you will see the base and height connected like this.

bxh 15 6 x 5 units 30 units Ifthen and the one-half a area triangle the area ofbase ais rectangle ofhalf times a triangle a rectangle, height. is bis… x h,

Does that only work with right triangles? NO

move rotate it toititform 180 a vertex, rectangle. Copy chop this scalene at thedegrees, triangle,

Area = ½ bh 8 m m 0 1 Area = (½)(10)(8) = 2 40 m

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b + b 1 2 h Area = 2 the average of the bases x the height