Another of the primary school many remember how to find the perimeter of any geometric shape: it is enough to know the length of all its sides and to find their sum.The perimeter is called the total length of the boundary of a plane figure.In other words, the sum of the lengths of its sides.Unit perimeter should correspond to the unit of measurement of its sides.Formula perimeter of the polygon has the form P = a + b + c ... + n, where P - perimeter, but a, b, c and n - length of each side.Otherwise, calculated the circumference (or perimeter of a circle) using the formula p = 2 * π * r, where r - radius and π - a constant approximately equal to 3.14.Consider a few simple examples that demonstrate how to find the perimeter.As an example we take shapes such as a square, rectangle, triangle, circle and a parallelogram.
How to find the perimeter of the square
square is called the right quadrangle, which are equal to all sides and angles.Since all the sides of the square equal the sum of the lengths of its sides can be calculated by the formula P = 4 * a, and where - the length of one side.Thus, the perimeter of a square with sides 16.5 cm is P = 4 * 16.5 = 66 cm. So it is possible to calculate the perimeter of an equilateral rhombus.
How to find the perimeter of a rectangle
Rectangle - a rectangle of which the corners are 90 degrees.It is known that in such a shape as a rectangle, the side lengths are equal in pairs.If the width and height of the rectangle have the same length, it is called a square.Typically, the length of a rectangle is called the greatest of the parties, and the width - the lowest.Thus, in order to receive the perimeter of the rectangle, it is necessary to double the amount of its height and width: P = 2 * (a + b), and where - the height and b - width.Due to the presence of a rectangle, one side of which is long and is 15 cm, and the other width of the set value is 5 cm, we obtain perimeter equal to P = 2 * (15 + 5) = 40 cm.
Asfind the perimeter of the triangle
triangle formed by three segments that connect the points (vertices of a triangle), not lying on the same line.Equilateral triangle is called if all three are equal to his hand, and isosceles if two equal sides.To find the perimeter of an equilateral triangle, the length of its sides must be multiplied by 3: R * a = 3, and where - one of its sides.If the sides of the triangle are not equal, it is necessary to conduct an operation of addition: P = a + b + c.The perimeter of an equilateral triangle with sides 33, 33 and 44, respectively, will be equal to: P = 33 + 33 + 44 = 110 cm.
How to find the perimeter of a parallelogram
Parallelogram - a quadrilateral with pairwise parallel opposite sides.The square, rhombus and rectangle shapes are special cases.Opposite sides of the parallelogram are all, therefore its perimeter calculation using formula P = 2 (a + b).The parallelogram with sides of 16 cm and 17 cm sum of the sides or perimeter is P = 2 * (16 + 17) = 66 cm.
How to find the circumference
Circle is a closed line, all points of which are located at equaldistance from the center.The length of a circle and its diameter is always have the same relation.This ratio is expressed in constant written using letters and π is approximately 3.14159.Explore the perimeter of the circle can be the product of the radius of 2 and π.It turns out that the length of a circle with a radius of 15 cm will be equal to P = 2 * 3.14159 * 15 = 94,2477
