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.