Question

A(2, 6), B(6, 6) and C(6, 3) are the coordinates of a triangle. D, E and F are the reflection points of A, B and C respectively about X = 0. G, H and K are the reflection points of D,E and F respectively about Y = 1. The value of (sum of the y - coordinates of H and K) - (sum of the x - coordinates of G and H) is

• A. 1
• B. 2
• C. 3
• D. 0

Answer 1

The correct option is C

3

Reflection about Y = 0,
X - coordinate remains the same
Y - coordinate's sign changes
Reflection about Y = a
X - coordinate remains the same
Y - coordinate's sign changes and the value is reduced by 2a
Sum of the y - coordinates of H and K = -4 - 1 = -5
Sum of the x - coordinates of G and H = -2 - 6 = -8
(Sum of the y - coordinates of H and K) - (Sum of the x - coordinates of G and H) = -5 + 8 = 3