Question

25 formula of maths for perimeter and area

Answer 1

Answer:

1) Perimeter of Square= 4a unit

(a is side of square)

2) Perimeter of rectangle= 2(l+b) unit

(l is length and b is breadth)

3) Perimeter of circle = 2 π r

( r is radius of circle)

4) Perimeter of Parallelogram= 2(l+b) unit

(l is length and b is breadth)

5) Perimeter of equilateral triangle = 3a unit

(where a is side of Equilateral triangle)

6) Perimeter of Isosceles triangle = (2a+b)unit

(where a is length of two equal side and b is base of isosceles triangle)

7) Perimeter of triangle = (a+b+c ) unit

(where a,b and c are sides of triangle)

8) Area of circle =

$\pi {r}^{2} \: \: {unit}^{2}$

9) Area of square =

${a}^{2} \: {unit}^{2}$

10) Area of rectangle =

$l \times b \: \: {unit}^{2}$

11) Area of triangle =

$\frac{1}{2} \times base \times height \: \: {unit}^{2}$

12) Area of Rhombus =

$\frac{1}{2} \: d1 \times d2 \: \: {unit}^{2}$
d1,d2 are diagonals of rhombus

13) Area of Parallelogram =

$b \times h \: \: {unit}^{2}$

b= base

h= perpendicular distance between parallel lines

14) Area of trapezium

$= \frac{1}{2} \times (sum \: of \: parallel \: sides) \times perpendicular \: distance \: \: {unit}^{2}$

15) Area of triangle=
$\sqrt{s(s - a)(s - b)(s - c)} \: \: {unit}^{2}$
where a,b and c are sides and S is semi-perimeter of triangle

16) Area of Equilateral triangle =

$\frac{ \sqrt{3} }{4} {a}^{2} \: \: {unit}^{2}$

17) Area of isosceles triangle=

$\frac{1 }{2}\times\:b\:\sqrt{{a}^{2}-\frac{{b}^{2}}{4}}\: \: {unit}^{2}$

(where a is length of two equal side and b is base of isosceles triangle)

18) Area of sector of a circle =

$\frac{\theta}{360}\times \pi {r}^{2} \: \: {unit}^{2}$

These are all about the formula's of 2-dimensional closed figures.