Grade 7 & 8 math tutorial on geometry for MATHCOUNTS, Math Kangaroo, and AMC8 Preparation.
An angle is the inclination to one another of two straight lines that meet. The point at which two lines meet is called the vertex of the angle. If a straight line that stands on another straight line makes the adjacent angles equal, then each of those angles is called a right angle; and the straight line that stands on the other is called a perpendicular to it. More...
If the sum of angle a and angle is 180 degree, then line1 and line2 are parallel. More...
An equilateral triangle has three equal sides. An isosceles triangle has two equal sides.
A scalene triangle has three unequal sides. A right triangle is a triangle that has a right angle. More...
Quadrilateral just means "four sides".
Rectilinear figures are figures bounded by straight lines. A triangle is bounded by three straight lines, a quadrilateral by four, and a polygon by more than four straight lines.
A circle is a plane figure bounded by one line, called the circumference, such that all straight lines drawn from a certain point within the figure to the circumference are equal to one another. That point is called the center of the circle. More...
Triangle
Area = ½ × b × h
b = base
h = vertical height More...
Triangle
Perimeter = a + b + c More...
Cube is a 3-dimensional shape with six square or rectangular sides. A typical example will be a dice.
Cuboid is a box-shaped 3-dimensional object. It has six flat faces and all angles are right angles. Cuboid is also called regular prism.
Cone is a shape whose base is a circle and whose sides taper up to a point. A familiar example will be an ice-cream cone. More...
| Cube | 6x2 | x is length of cube edge |
| Cuboid | 2xy + 2xz + 2yz | x, y, z are the length of cuboid's 3 edges |
| Prism | Total surface area = 2 × BA + BP × L | BA is base area, BP is base perimeter, L is length |
| Cylinder | Area of curved surface = 2π rh Area of each end = π r² Total surface area = 2π rh + 2π r² |
r is radius of the end circle; h is height of cylinder |
| Sphere | 4π r² | r is radius of sphere |
