Question

Using a graph paper, plot the points A(6, 4) and B(0, 4).

1. Reflect A and B in the origin to get the images A' and B'.
2. Write the co-ordinates of A' and B'.
3. State the geometrical name for the figure ABA'B'.
4. Find its perimeter.

Answer 1

a.

b. Co-ordinates of A' = (–6, –4)

Co-ordinates of B' = (0, –4)

c. ABA'B' is a parallelogram.

d. In ΔBA'B', BB' = 8 units, A'B' = 6 units

∴ BA' = `sqrt(6^2 + 8^2)`

= `sqrt(36 + 64)`

= `sqrt(100)`

= 10 units

`\implies` B'A = 10 units

AB = A'B' = 6 units

Perimeter of ABA'B'

= AB + BA' + A'B' + B'A

= 6 + 10 + 6 + 10

= 32 units