Key Concepts

• Properties of Rectangles
  • Rectangles have four sides and four right ([latex]90^\circ[/latex]) angles.
  • The lengths of opposite sides are equal.
  • The perimeter, [latex]P[/latex] , of a rectangle is the sum of twice the length and twice the width.
    • [latex]P=2L+2W[/latex]
  • The area, [latex]A[/latex] , of a rectangle is the length times the width.
    • [latex]A=L\cdot W[/latex]
• Triangle Properties
  • For any triangle [latex]\Delta ABC[/latex] , the sum of the measures of the angles is [latex]180^\circ[/latex].
    • [latex]m\angle A+m\angle B+m\angle C=180^\circ [/latex]
  • The perimeter of a triangle is the sum of the lengths of the sides.
    • [latex]P=a+b+c[/latex]
  • The area of a triangle is one-half the base, [latex]b[/latex], times the height, [latex]h[/latex].
    • [latex]A=\Large\frac{1}{2}\normalsize bh[/latex]
• Trapezoid properties
  • A trapezoid has a larger base, [latex]B[/latex], and a smaller base, [latex]b[/latex]. The height [latex]h[/latex] is the distance between the bases.
  • The formula for the area of a trapezoid is one-half the height, [latex]h[/latex], times the sum of the big base, [latex]B[/latex], plus the little base, [latex]b[/latex].
    • [latex]{\text{Area}}_{\text{trapezoid}}=\Large\frac{1}{2}\normalsize h\left(b+B\right)[/latex]

Glossary

area

The area is a measure of the surface covered by a figure.

equilateral triangle

A triangle with all three sides of equal length is called an equilateral triangle.

isosceles triangle

A triangle with two sides of equal length is called an isosceles triangle.

perimeter

The perimeter is a measure of the distance around a figure.

rectangle

A rectangle is a geometric figure that has four sides and four right angles.

trapezoid

A trapezoid is four-sided figure, a quadrilateral, with two sides that are parallel and two sides that are not.

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