Soran University

Faculty of Engineering - Civil Engineering Department

ANGLE DETERMINATION

Student: Sarchia KhursheedGroup: 2nd

Date: 26.04.2016Supervisor: Eng. Anwar Jabbar

IntroductionJust like regular numbers, angles can be added to obtain a sum, perhaps for the purpose of determining the measure of an unknown angle.

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Sometimes we can determine a missing angle because we know that the sum must be a certain value. The sum of the degree measures of angles in any triangle equals 180 degrees.In right hand there is a picture of triangle ABC, where angle A = 60 degrees, angle B = 50 degrees and angle C = 70 degrees.If we add all three angles in any triangle we get 180 degrees. So, the measure of angle A + angle B + angle C = 180 degrees. This is true for any triangle in the world of geometry. We can use this idea to find the measure of angle(s) where the degree measure is missing or not given.We have another rule for measuring angles when we have the dimensions of the triangle which called the Law of Cosines (also called the Cosine Rule) which is very useful for solving triangles: c2 = a2 + b2 – 2ab cos θ

ObjectiveTo determine the angles of a triangle with known distances of sides.

Equipment Measuring Tape or Wheel Measuring Roller Steel Rods Rope Hammer

Procedure1. Select four points on the ground, install a steel rod at each

point.2. Connecting all the points by a thin rope, also connect points

diagonally.3. Take all dimensions between points by measuring tape.4. By connecting points diagonally we getting two triangles, we

can obtain the angles of triangles by cosine rule.

Data and Calculation

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c2 = a2 + b2 – 2ab cos θ => cos θ = a2+b2−c2

2ab

θ1 : 103.73o

θ2 : 80.16o

θ3 : 100.94o

θ4 : 76.05o

Result and ConclusionIn conclusion we know that by knowing the distances of triangle’s slides we can obtain the desired angle. We use this method to determine the angles of a parallelogram. We divide the parallelogram into two triangles by creating two diagonal lines, and then using cosine law for obtaining each angles, and finally we take sum of all angles and it must be 360o.

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