Displaying items by tag: properties

General Geometric Shapes

Square

MathNotes 2pogs 1

  • All sides are equal
  • Opposite sides are parallel
  • Each interior angle is a right angle (90º)
  • The interior angles total up to 360º
  • Diagonals bisect each other at right angles.
  • Diagonals measure the same length and bisect interior angles.

Rectangle

MathNotes 2pogs 2

 

  • Each interior angle is 90º and they all add up to 360º
  • Diagonals are equal
  • Diagonals bisect each other but NOT at right angles

Parallelogram

MathNotes 2pogs 3

  • Opposite sides are equal and parallel
  • Opposite angles are equal
  • Diagonals bisect each other
  • Diagonals are not equal
  • Adjacent angles are supplementary (add up to 180º)

Rhombus

MathNotes 2pogs 4 

  • All sides are equal
  • Opposite sides are parallel
  • Opposite angles are equal
  • Diagonals bisect each other at 90º
  • Diagonals bisect the interior angles

Trapezium

MathNotes 2pogs 5

  • The sum of the interior angles is 360º
  • Has a pair of parallel lines which are not of the same length
  • Has a perpendicular height joining the two parallel lines

Right-angled Triangle (Pythagorean relationship)

MathNotes 2pogs 6

 

  • H2 = b2 + h2
  • b2 = H2 – h2
  • H2 = H2 - b2
    Examples of relationships
    Base Height Hypotenuse
     3  4  5
     6  8  10
     5  12  13
     7  24  25
     8  15  17
     9  40  41

Properties of Triangles and Parallel Lines

Triangle

Exterior angles & interior angles
MathNotes 2pogs 9

  • Angles x, y, and z are exterior angles while a, b, and c are interior angles.
  • Exterior angles add up to 360º while interior angles add up to 180º.
  • Angles x, a; b, z; and c, y; are adjacent to each other and they add up to 180º (supplementary angles)

Parallel Lines and Transversal

MathNotes 2pogs 10

  1. Angles at a point e.g. a + b+ c + d = 360º
  2. Vertically opposite e.g. a/d, b/c, f/g, e/h. They are equal
  3. Corresponding angles e.g. b/f, a/e, c/g, d/h. They are equal
  4. Alternate angles e.g. c/f, d/e are always equal.
  5. Co-interior angles e.g. c/e, d/f, are always equal.
  6. Co-interior/allied angles e.g. c/e, d/f are formed by parallel lines. They are supplementary.

Speed, Distance and Time

The formulae related to speed, distance and time can be derived from the following triangle.
dst