Instruction

1

To calculate the value of an acute angle in a right triangle, you need to know the values of all its sides. Take the necessary notation for the elements of a right triangle:

c is the hypotenuse;

a,b are the legs;

A – Acute angle, which is opposite side b;

B – Sharp corner, which is opposite side a.

c is the hypotenuse;

a,b are the legs;

A – Acute angle, which is opposite side b;

B – Sharp corner, which is opposite side a.

2

Calculate the length of the sides of the triangle, which is unknown, using the Pythagorean theorem. If you know a leg and the hypotenuse is c, we can calculate the side b; why subtract the square of the length of the hypotenuse c, the square of the length of side a, then remove from the resulting values of the square root.

3

Similarly, you can calculate the side a, if we know the hypotenuse c and side b, from the c square of the hypotenuse subtract the square of side b. Then from the result extract the square root. If you know two sides and need to find the hypotenuse, add the squares of the lengths of the legs and from the resulting values, extract the square root.

4

The formula for trigonometric functions calculate the sine of the angle A: sinA=a/c. In order for the result to be more accurate, use a calculator. The resulting value is rounded to 4 digits after the decimal point. Similarly, find the sine of angle B, what is sinB=b/c.

5

Using the "four-digit mathematical tables" Bradis, find the values of angles in degrees using the known values of the sines of these angles. To do this, open table VIII "Table" Bradis and look at the value previously calculated sinuses. In this table the first column "A" has a value of the desired angle in degrees. In the column, where the value of the sinus, in the upper line "A", find the minutes value for the angle.

Note

Table Bradis contain values limited to four digits after the decimal point, so round obtained in the course of computing the values up to this limit.

Useful advice

To determine the angle after calculation of the value of its sine, you can use a calculator that has trigonometric functions.

# Advice 2: How to calculate the sine of the angle

When you have to deal with solving applied problems involving trigonometric functions, most commonly required to compute values

**of the sine**or co**sine**of the specified**angle**.Instruction

1

The first option is classic, using paper, protractor, and pencil (or pen).By definition the sine

**of an angle**is the ratio of the opposite leg to the hypotenuse of a right triangle. That is, to calculate the value you need with the help of a protractor to construct a right triangle one of whose angles is equal to the sine of which you are interested in. Then measure the length of the hypotenuse and opposite side and divide the second into first with the desired degree of accuracy.2

The second option is the school. From school we all remember the tables Bradis" containing thousands of values of trigonometric functions from different angles. You can look for as a paper edition and its electronic equivalent in pdf format - they are in the network. Finding a table to find the value of

**sine**of the desired**angle**is not difficult.3

The third option is optimal. If you have access to a computer, you can use a standard calculator Windows. It should be switched to advanced mode. To do this, under "View" menu, select "Engineering." View of the calculator will change - it will, in particular, the buttons to compute trigonometric functions.Now enter the value

**of angle**, sine of which you want to calculate. You can do it from the keyboard and clicking the mouse cursor on the keys of the calculator. And you can just copy and paste the value (CTRL + C and CTRL + V). Then select a unit of measure, which must be calculated the answer for trigonometric functions it can be radians, degrees or happy. This is done by selecting one of three values switch located below the input field calculated value. Now by pressing the button labeled "sin", will get an answer to your question.4

The fourth option is the most modern. In the era of the Internet in the network there are resources that offer you to deal with almost every encountered in life the problem. Online calculators trigonometric functions with user friendly interface, more advanced functionality is not difficult. The best of them suggest to calculate not only the values of the individual functions, but rather complicated expressions of several functions.