Question

How will you construct a ${150}^o$ angle?

Answer 1

Step 1: Compute how 150 can be expressed
${150}^o={180}^o-{30}^o$
30 degrees is half of 60 degrees which is an angle of equilateral triangle

Step 2: Draw a line segment AB
Step 3: Choose a point C on AB and with BC as radius and centre as C, draw an arc. Again, with same radius but centre as B, draw another arc such that it cuts the previous arc at D. Now as $BC=CD=BD$, hence angle DCB would be ${60}^o$
Step 4: Draw an arc with centre as D and radius as BC. Draw another arc with same radius but centre as B such that it cuts the previous arc at E. This will make EC the bisector of the angle BCD. Hence angle BCE is ${30}^o$
So, angle ACE of 150 degrees is constructed