You will need
• calculator;
• - the range.
Instruction
1
To find the number of square centimeters (square) in the rectangle, multiply the length of the rectangle by its width. That is, use the formula:

KKS = L * W,

where:

D – length of the rectangle
W – its width, and
KKS – the number of square inches (square).

To area turned out in square centimeters (cm2), length and width of the rectangle pre-move in centimeters.
2
Example: a rectangle has a length of 2 cm and a width of 15 mm.

Question: how many square inches equals the area of the rectangle?

Solution:
15 mm = 1.5 cm.
2 (cm) * 1.5 (cm) = 3 (cm2).

Answer: the area of a rectangle is 3 cm2.
3
To find the area of a right triangle, multiply the lengths of its sides, and divide the product by 2.
To find the number of square centimeters in an arbitrary triangle, multiply the height and base of the triangle, then divide the resulting value in half.
4
If you know the lengths of the sides of the triangle, then calculate its square, use the formula of Heron:

KKS = √(p * (p-a) * (p-b) * (p-C)),

where p is properiter triangle, i.e. p=(a+b+C)/2,
where a, b, C the lengths of the sides of the triangle.
5
To calculate the area of a circle use the formula (PR Kvadrat). If the circle is incomplete (sector), multiply the area of the corresponding circle by the number of degrees in the sector, and then divide by 360.
The lengths of the sides of the triangle and its height, and the radius of the circle must be expressed in inches.
6
Example: the length of the diagonal of the screen of the standard monitor is 17 inches.

Question: how many square inches is the screen?

Solution: as in one inch contains 2.54 cm, the length of the diagonal of the screen of monitor will be equal to 2.54 * 17 = 43,18 cm
Denote by a, b, d length, width and size of the diagonal, respectively. Then by the Pythagorean theorem:
d2 = a2+b2.
As the aspect ratio is standard (not widescreen) display is 3:4, then a = 4/3 * b, where:
a2+b2=(4/3 * b)2 + b2=7/3 * b2.
Substituting the value of d=43,18, we get:
(43,18)2 = 7/3 * b2.
Therefore, b=28,268, a=37,691.
Therefore, the area of the screen is: 1065,438 (cm2)

Response: the area of the screen semnadtsatiletnego standard monitor is 1065,44 cm2.