Construct at least 4 different angles. Draw their bisectors.
Step 1: Draw an angle ∠XOY.
Step 2: With O as centre and any convenient radius, draw an arc cutting OX at A and OY at B.
Step 3: With A as centre and any radius greater than half of AB, draw an arc.
Step 4: With B as centre and the same radius, draw another arc intersecting the previous arc at C.
Step 5: Join OC. OC is the angle bisector of ∠XOY.
Why it works: Triangles OAC and OBC are congruent by SSS (OA = OB, AC = BC, OC is common), making ∠AOC = ∠BOC.
Explanation
The chapter explains angle bisection using congruent triangles. When OA = OB (by construction) and AC = BC (by using the same radius), triangles OAC and OBC are congruent by the SSS condition. Therefore, ∠AOC = ∠BOC, meaning OC bisects the angle. Students should practice this construction with various angles (acute, obtuse, right angles) to develop proficiency.
Solution Steps
Draw an angle ∠XOY.
With O as centre and any convenient radius, draw an arc cutting OX at A and OY at B.
With A as centre and any radius greater than half of AB, draw an arc.
With B as centre and the same radius, draw another arc intersecting the previous arc at C.
Join OC. OC is the angle bisector of ∠XOY.