formulas Flashcards
(a+b)2
a2 + 2ab + b2
(a-b)2
a2 + b2 - 2ab
(a-b) (a+b)
a2 - b2
(x+a)(x+b)
x2 + (a+b)2 + ab
(a+b)2 + (a-b)2
2(a2 + b2)
(a+b)2 - (a-b)2
4ab
a2 + b2
(a+b) - 2ab
xm xn
x m+n
xm/xn
x m-n
(x m)n
x mn
number of diagonals in a polygon
n (n-3)/ 2
exterior angle property
The sum of exterior angles in a polygon is always equal to 360 degrees. Therefore, for all equiangular polygons, the measure of one exterior angle is equal to 360 divided by the number of sides in the polygon.
no. of sides of polygon
( n - 2 ) × 180 °
divisibility law of 3
sum of digits
divisibility law of 4
last 2 digits
divisibility law of 6
divisible by 2 & 3
divisibility law of 8
last 3 digits
divisibility law of 9
sum of digits
divisibility law of 12
divisible by 3 & 4
divisibility law of 11
if the difference between the sum of the digits at the odd and even places equals 0 or divisible by 11, then the number is divisible by 11.
profit =
SP - CP
loss =
CP - SP
SP =
profit + CP /
CP - loss
profit %
profit * 100 / CP
loss %
loss * 100 / CP
SI =
PRT/100
CI =
A = P (1+R/100)N CI = A - P
CI (half yearly) =
first divide the R/2
and then multiply the n*2
then use this formula
A = P(1+R/100)N
CI (quarter yearly) =
first divide the R/4
and then multiply the n*4
then use this formula
A = P(1+R/100)N
discount % =
(discount/list price)*100
percent formula =
(value/total value)×100
percent increase/decreases formula =
(actual increase/decrease)/original amount *100
properties of square
All the sides of the square are of equal measure
The sides are parallel to each other
All the interior angles of a square are at 90 degrees (i.e., right angle)
The diagonals of a square perpendicular bisect each other
properties of rectangle
The opposite sides of a rectangle are of equal length
The opposite sides are parallel to each other
All the interior angles of a rectangle are at 90 degrees.
The diagonals of a rectangle bisect each other.
properties of rhombus
All the four sides of a rhombus are of the same measure
The opposite sides of the rhombus are parallel to each other
The opposite angles are of the same measure
The sum of any two adjacent angles of a rhombus is equal to 180 degrees
The diagonals perpendicularly bisect each other
properties of parallelogram
The opposite side of the parallelogram are of the same length
The opposite sides are parallel to each other
The diagonals of a parallelogram bisect each other
The opposite angles are of equal measure
The sum of two adjacent angles of a parallelogram is equal to 180 degrees
properties of trapezium
Only one pair of the opposite side of a trapezium is parallel to each other
The two adjacent sides of a trapezium are supplementary (180 degrees)
The diagonals of a trapezium bisect each other in the same ratio
properties of kite
The pair of adjacent sides of a kite are of the same length
The largest diagonal of a kite bisect the smallest diagonal
Only one pair of opposite angles are of the same measure.
