Sometimes in life it is necessary to come up against situations in which knowledge from geometry is necessary. Such information in everyday life are seldom used therefore it is forgotten. One of demanded questions is search of the area of a triangle by means of length of two of its parties.
It is required to you
- - ruler;
- - protractor;
- - calculator.
Instruction
1. The area of a triangle calculated on length of two of its parties demands also measurement of a corner between them. For this purpose use a protractor or other special tools. For example, Mulka - is very convenient for measurement of corners in the room.
2. After you found the size of two parties of a triangle and corner between them, pass to calculations. It is necessary to find the area on the following formula: S ∆ abc = 1/2 ab sin of a corner. At the same time, if you have a right angle in a triangle between two known parties, then the formula can be reduced: S ∆ abc = 1/2 ab.
3. To calculate a sine of the angle it is possible to use the trigonometrical table of Bradis where values for the most widespread sizes of corners are given. One more quite good way for calculation of a sine of the angle is the calculator. In each Windows operating system it is among standard programs. Open it and switch to the Engineering mode which is in the section "Look". Then you enter the size of a corner which sine you want to calculate. Farther choose units of measure for the counted answer. It can be degrees, radians or are glad. It is possible to make it by means of the buttons located under the entry field. Press the sin key and receive result.
4. Of course, the sine of the angle can be calculated also by means of various calculators advanced online with the convenient interface and big functionality today. It is possible to find such program in the Internet because them it is offered much. Just enter in search engine "calculator of trigonometrical functions".
5. Now multiply lengths of two parties of a triangle and a sine of the angle between them, you divide everything into 2 and the answer is ready. The area of a triangle is found.