8th Grade Math Formulas Flashcards

Square

• Perimeter formula: ( P = 4s ) (where ( s ) is the side length)
• Area formula: ( A = s^2 )

Circle

• Circumference formula: ( C = 2\pi r ) (where ( r ) is the radius)
• Area formula: ( A = \pi r^2 )

Rectangle

• Perimeter formula: ( P = 2l + 2w ) (where ( l ) is the length and ( w ) is the width)
• Area formula: ( A = L \times W )

Triangle

• Perimeter formula: ( P = a + b + c ) (where ( a ), ( b ), and ( c ) are the lengths of the sides)
• Area formula: ( A = \frac{1}{2} b \times h ) (where ( b ) is the base and ( h ) is the height)
• Sum of angles in a triangle equals 180 degrees
• Pythagorean Theorem: ( a^2 + b^2 = c^2 ) (applies to right-angled triangles)

Parallelogram

• Perimeter formula: ( P = 2a + 2b ) (where ( a ) and ( b ) are the lengths of the sides)
• Area formula: ( A = b \times h ) (where ( b ) is the base and ( h ) is the height)

Trapezoid

• Area formula: ( A = \frac{1}{2} h (b_1 + b_2) ) (where ( h ) is the height and ( b_1, b_2 ) are the lengths of the bases)

Slant Height

• Defined as the diagonal distance from the top point of a cone or pyramid to the base

General Prisms

• Volume formula: ( V = \text{Area of base} \times \text{height} )
• Surface Area is the sum of all face areas

Cylinder

• Volume formula: ( V = \text{Area of base} \times \text{height} )
• Surface area formula: ( SA = (2 \times \text{Area of base}) + (\text{Circumference} \times \text{height}) )

Right Pyramid

• Volume formula: ( V = \frac{1}{3} \times \text{Area of base} \times \text{height} )
• Surface area formula: ( SA = \text{Area of base} + \left( \frac{1}{2} \times \text{perimeter of base} \times \text{slant height} \right) )

Circular Cone

• Volume formula: ( V = \frac{1}{3} \times \text{Area of base} \times \text{height} )
• Surface area formula: ( SA = \text{Area of base} + \left( \frac{1}{2} \times \text{Circumference} \times \text{slant height} \right) )

Sphere

• Volume formula: ( V = \frac{4}{3} \pi r^3 ) (where ( r ) is the radius)
• Surface area formula: ( SA = 4 \pi r^2 )

Rectangular Prism

• Volume formula: ( V = L \times W \times H ) (where ( L ), ( W ), and ( H ) are the dimensions)
• Surface area formula: ( SA = 2(LW + LH + WH) )