Question

How to make an angle of 75°?

Answer 1

first construct y
60 degree and 90 degree

then
bisect the angle lying between them
u will get 75 degree

Answer 2

Answer :


STEPS OF CONSTRUCTION -

1. Draw angle ABE = 60° and ABF = 90°

2. Let ray BF intersects the arc of circle at G.

3. Now with M as centre and radius greater than the half of MG, draw an arc.

4. With G as centre and with same radius as in step 3 ; draw an arc which intersect the previous arc at point H.

5. Draw a ray BC passing through H which bisects angle EBF.

Thus angle ABC = 75° is the required angle.


VERIFICATION - Measure angle ABC with protractor. We observe Angle ABC = 75°.


JUSTIFICATION -

angle EBF = angle ABF - angle ABE = 90° - 60° = 30°

angle EBC = angle CBF

= 1/2 of angle EBF = 1/2 of 30° = 15°
[ BC is the bisector of angle EBF ]

therefore, angle ABC = angle ABE + angle EBC

= 60° + 15°

=> angle ABC = 75°
(which is true when measured with protractor)