Question: 18. Consider the parallelogram ABCD that has been graphed on the number plane.
18a Find the gradient of sides AB and CD.
gradient of AB =
gradient of CD =
Graph: A parallelogram labeled A, B, C, D is on the number plane with points approximately A(2,2), B(8,6), C(6,8), and D(0,4); it is in the top-left.
1. **State the problem:** We need to find the gradients (slopes) of sides $AB$ and $CD$ of the parallelogram $ABCD$ with points $A(2,2)$, $B(8,6)$, $C(6,8)$, and $D(0,4)$.
2. **Formula for gradient:** The gradient $m$ between two points $(x_1,y_1)$ and $(x_2,y_2)$ is given by
$$m = \frac{y_2 - y_1}{x_2 - x_1}$$
3. **Calculate gradient of $AB$:**
Points: $A(2,2)$ and $B(8,6)$
$$m_{AB} = \frac{6 - 2}{8 - 2} = \frac{4}{6}$$
Simplify the fraction:
$$m_{AB} = \frac{\cancel{4}}{\cancel{6}} = \frac{2}{3}$$
4. **Calculate gradient of $CD$:**
Points: $C(6,8)$ and $D(0,4)$
$$m_{CD} = \frac{4 - 8}{0 - 6} = \frac{-4}{-6}$$
Simplify the fraction:
$$m_{CD} = \frac{\cancel{-4}}{\cancel{-6}} = \frac{2}{3}$$
5. **Interpretation:** Both sides $AB$ and $CD$ have the same gradient $\frac{2}{3}$, which confirms that these opposite sides of the parallelogram are parallel as expected.
**Final answers:**
$$\text{gradient of } AB = \frac{2}{3}$$
$$\text{gradient of } CD = \frac{2}{3}$$