120 Angle Math

Complementary and supplementary angles.

120 angle math. We are given a 120 degrees angle with vertex p and an equilateral triangle abc inscribed in it such that the vertices a and b lie on the sides of the angle and c is in its interior as in the drawing. Measuring degrees we often measure degrees using a protractor. 18 20 24 30 36 40 45 60 72 90 120 and 180 which makes a lot of basic geometry easier. Bisection is shown in bisecting an angle.

For example constructing a 30 angle and then bisecting it you get two 15 angles. Equation of an ellipse. This gives you some more angles to combine as described above. Sure a 120 angle is the adjacent angle to any of the 60 angles you already constructed.

For example a 60 angle can be used to create a 120 angle by constructing its supplementary angle. The normal protractor measures 0 to 180. Show that the line pc bisects the angle apb i e that the angles apc and cpb are both 60 degrees. Angle bisectors and medians.

An activity involving a compass and a ruler. Angles can also be measured in radians note. Constructing a 60 degree angle constructing a 30 degree angle constructing a 120 degree angle and constructing a 90 degree angle using a compass. By constructing the supplementary angle of a given angle you get another one to combine as above.

For those who want to learn more. Year 8 interactive maths second edition. Classifying and constructing angles by their measurement.