Instruction

1

If it is possible to use the appropriate measuring device, select the one that best meets the task. For example, to determine the value

**of the angle**drawn on paper or other similar material, quite suitable protractor, for determining the angular directions of the terrain have to look for the geodetic theodolite. For measuring angles between adjacent planes of any volume of items or units of use protractors - there are many types, different device, method of measurement and accuracy. You can find more exotic instruments measure angles in**degrees**.2

If the possibility of measurement using the appropriate tool is missing, then use is known from school trigonometric relations between the lengths of sides and angle measures of the triangle. It will be enough possible to measure angular and linear dimensions - e.g., using rulers, tape measures, meter, pedometer, etc. With this start - measure from the top

**corner**along two of its sides convenient distance, write down the values of these two sides of a triangle, and then measure the length of the third side (the distance between the endings of those parties).3

Select to calculate the value

**of the angle**in**degrees**of one of the trigonometric functions. For example, you can use the theorem of cosines: the square of the length of the side lying opposite the measured**angle**equal to the sum of the squares of the other two sides minus twice the product of the lengths of these sides into the cosine of the desired**angle**(a2 = b2+c2-2*b*c*cos(α)). From this theorem, print the value of cosine: cos(α) = (b2+c2-a2)/(2*b*c). Trigonometric function, which restores the value of the cosine**of the angle**in**degrees**, called the arc cosine, this means that the formula in its final form should look like this: α = arccos((b2+c2-a2)/(2*b*c)).4

Substitute the measured dimensions of the sides of the triangle obtained in the previous step, the formula and perform the calculation. This can be done using any calculator, including those that offer various online services on the Internet.