Grandfathering Pr.1-3 Cr By Age 50

Area - Facts & Formulae

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I.FACTS ON TRIANGLES:

  1. Sum of the angles of a triangle is 180 degrees.
  2. Sum of any two sides of a triangle is greater than the third side.
  3. Pythagoras theorem:
    In a right angle triangle,
    (Hypotenuse)^2 = (base)^2 + (Height)^2
  4. The line joining the midpoint of a side of a triangle to the opposite vertex is called the MEDIAN
  5. The point where the three medians of a triangle meet is called CENTROID.
    Centroid divides each of the medians in the ratio 2:1.
  6. In an isosceles triangle, the altitude from the vertex bi-sects the base
  7. The median of a triangle divides it into two triangles of the same area.
  8. Area of a triangle formed by joining the midpoints of the sides of a given triangle is one-fourth of the area of the given triangle.

II.FACTS ON QUADRILATERALS:

  1. The diagonals of a parallelogram bisects each other .
  2. Each diagonal of a parallelogram divides it into two triangles of the same area
  3. The diagonals of a rectangle are equal and bisect each other.
  4. The diagonals of a square are equal and bisect each other at right angles.
  5. The diagonals of a rhombus are unequal and bisect each other at right angles.
  6. A parallelogram and a rectangle on the same base and between the same parallels are equal in area.
  7. Of all the parallelograms of a given sides , the parallelogram which is a rectangle has the greatest area.