villaarchi.blogg.se - The area of a rectangle

#THE AREA OF A RECTANGLE HOW TO#
#THE AREA OF A RECTANGLE FULL#

The area of one rectangular window is (G × F) 1.2 × 2.7 = 3.24m 2. The area of the door and steps is (D × E) 4.5 × 2.3 = 10.35m 2.

#THE AREA OF A RECTANGLE FULL#

Next, work out the areas of the windows and doors, so they can be subtracted from the full area. The combined full area of the front of the house is the sum of the areas of the rectangle and triangle: The area of the triangle is therefore (2.1 × C) ÷ 2. The height of the triangle is (A – B) 9.7 – 7.6 = 2.1. This example pulls on much of the content of this page for solving simple area problems.įirst, work out the area of the main shape of the house – that is the rectangle and triangle that make up the shape. The area of a circle with a diameter of 3m is 7.0695m 2. Therefore a circle with a radius of 5cm has an area of:Ī circle with a diameter of 3m has an area:įirst, we work out the radius (3m ÷ 2 = 1.5m) R 2 (radius squared) means radius × radius. You need the radius to work out the area of a circle, the formula is: In practice, when measuring circles it is often easier to measure the diameter, then divide by 2 to find the radius.

You can measure the diameter or radius at any point around the circle – the important thing is to measure using a straight line that passes through (diameter) or ends at (radius) the centre of the circle. The radius of a circle is the length of a straight line from the central point of the circle to its edge.

The diameter is twice the length of the radius (diameter = radius × 2) The diameter of a circle is the length of a straight line from one side of the circle to the other that passes through the central point of the circle. In order to calculate the area of a circle you need to know its diameter or radius. And don’t forget, if you need to apply more than one coat of paint, you must multiply the quantity of paint for one coat by the number of coats required! This will allow for any wastage and leave most of a litre left over for touching up at a later date. So you will probably round up to the next whole litre and buy two 5 litre cans and two 1 litre cans making a total of 12 litres of paint. You may be tempted to round down to 11 litres but, assuming we don’t water down the paint, that won’t be quite enough. In reality you may find that paint is only sold in 5 litre or 1 litre cans, the result is just over 11 litres. You can now work out the area of the two parts of the wall:Īrea of the rectangular part of the wall: 6.6 × 11.6 = 76.56m 2Īrea of the triangular part of the wall: (5.8 × 11.6) ÷ 2 = 33.64m 2Īdd these two areas together to find the total area:Īs you know that one litre of paint covers 10m 2 of wall so we can work out how many litres we need to buy: For example, the wall of a room may look like a square but when you measure it you find it is actually a rectangle. It is good practice to check that a shape is actually a square by measuring two sides. This is the same as saying length 2 or length squared. To find the area of a rectangle, multiply its height by its width.įor a square you only need to find the length of one of the sides (as each side is the same length) and then multiply this by itself to find the area. The simplest (and most commonly used) area calculations are for squares and rectangles. Squares and Rectangles and Parallelograms

#THE AREA OF A RECTANGLE HOW TO#

The remainder of this page explains and gives examples of how to calculate the area of a shape without using the grid system. Īlthough using a grid and counting squares within a shape is a very simple way of learning the concepts of area it is less useful for finding exact areas with more complex shapes, when there may be many fractions of grid squares to add together.Īrea can be calculated using simple formulae, depending on the type of shape you are working with. The area of this square is therefore 30.25cm 2.

Add the whole squares and fractions together: 25 + 5 + 0.25 = 30.25.

There is also 1 quarter square (shaded in green) – (¼ or 0.25 of a whole square).

10 half grid squares (shaded in yellow) – 10 half squares is the same as 5 full squares.

There are 25 full grid squares (shaded in blue).

We can still calculate the area by counting grid squares. We reject the case of L = 0 L = 0 L = 0, to obtain L = 4 L = 4 L = 4.In this example the square does not fit exactly onto the grid. Therefore, the area of the desk is 7 × 6 = 42 ft 2 7\times 6=42~\text = 4 L L 2 = area = perimeter = 4 L. The length is 7 7 7 feet, while the breadth is 6 6 6 feet. What is the area (in feet 2 ^2 2) that his desk occupies? Calvin's desk at work measures 7 7 7 feet by 6 6 6 feet.