maths formals 9th class
Answers
Geometry
Geometry Shapes Formulas for Class 9
Geometric Figure Area Perimeter
Rectangle A= l × w P = 2 × (l+w )
Triangle A = (1⁄2) × b × h P = a + b + c
Trapezoid A = (1⁄2) × h × (b1+ b2) P = a + b + c + d
Parallelogram A = b × h P = 2 (b + h)
Circle A = π r2 C = 2 π r
Algebra
Algebraic Identities For Class 9
(a+b)2=a2+2ab+b2
(a−b)2=a2−2ab+b2
(a+b)(a–b)=a2–b2
(x+a)(x+b)=x2+(a+b)x+ab
(x+a)(x–b)=x2+(a–b)x–ab
(x–a)(x+b)=x2+(b–a)x–ab
(x–a)(x–b)=x2–(a+b)x+ab
(a+b)3=a3+b3+3ab(a+b)
(a–b)3=a3–b3–3ab(a–b)
(x+y+z)2=x2+y2+z2+2xy+2yz+2xz
(x+y–z)2=x2+y2+z2+2xy–2yz–2xz
(x–y+z)2=x2+y2+z2–2xy–2yz+2xz
(x–y–z)2=x2+y2+z2–2xy+2yz–2xz
x3+y3+z3–3xyz=(x+y+z)(x2+y2+z2–xy–yz−xz)
x2+y2=12[(x+y)2+(x–y)2]
(x+a)(x+b)(x+c)=x3+(a+b+c)x2+(ab+bc+ca)x+abc
x3+y3=(x+y)(x2–xy+y2)
x3–y3=(x–y)(x2+xy+y2)
x2+y2+z2−xy–yz–zx=12[(x−y)2+(y−z)2+(z−x)2]<
Surface Area and Volumes
Shape Surface Area Volume
Cuboid 2(lb + bh +lh)
l= length, b=breadth, h=height
lbh
Cube 6a2 a3
Cylinder 2πr(h+r)
r = radius of circular bases
h = height of cylinder
πr2h
Cone πr(l+r)
r=radius of base
l=slant height
Also, l2=h2+r2, where h is the height of cone
(1/3)πr2h
Sphere 4πr2 (4/3)πr3
Step-by-step explanation:
I am also in class 9
Step-by-step explanation:
hope this will help u.....
