Page 288 - ICSE Math 7

CONSTRUCTIONS

Construction of a unique triangle is possible in the following cases:
(a) SSS criterion – three sides are given.
(b) ASA criterion – two angles and an included angle are given.
(c) SAS criterion – two sides and an included angle are given.
(d) RHS criterion – hypotenuse and a side of right triangle are given.

DATA HANDLING
Sum of all observations
• Mean =
Total number of observations

• Median of n observations all arranged in an order is:
 n + 1
(a)   th observation, when n is odd
 2 
n
  n 
 th +  2 + 1 th

2
(b)    observation, when n is even
2
PERIMETER AND AREA
Perimeter of a rectangle = 2 × (length + breadth)
Perimeter of a square = 4 × side
Area of a rectangle = length × breadth
Area of a square = side × side

1
Area of a triangle = × base × height
2
Area of a parallelogram = base × height
22
Circumference of a circle = 2pr; p = or 3.14
7
2
Area of a circle = pr ; p = 22 or 3.14
7
Area of a circular ring = Area of outer circle – Area of inner circle
2
2
= pR – pr ; R > r O R
2
2
= p(R – r ) r D C
H G
Area between two rectangles = Area of outer rectangle – Area of inner rectangle
E F
A B
PROBABILITY
Favourable Outcomes m
• P(A) = =
Total outcomes n
m = number of favourable outcomes
n = number of total outcomes
• P(A) + P( A ) = 1; 0 ≤ P(A) ≤ 1

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