Question

what is the area of △bcd? area = square units

Explanation:

Step1: Identify base and height

From the graph, for $\triangle BCD$, if we consider the horizontal - line segment $CD$ as the base and the vertical distance from $B$ to $CD$ as the height. The coordinates of $C=(3,10)$, $D=(7,10)$ and $B=(3, - 8)$. The length of the base $CD$ is calculated by the difference in $x$ - coordinates of $C$ and $D$. The height is calculated by the difference in $y$ - coordinates of a point on $CD$ (e.g., $C$) and $B$.
The length of $CD=\vert7 - 3\vert=4$.
The height from $B$ to $CD$ is $\vert10-( - 8)\vert = 18$.

Step2: Apply area formula

The area formula for a triangle is $A=\frac{1}{2}\times base\times height$.
Substitute base = 4 and height = 18 into the formula: $A=\frac{1}{2}\times4\times18$.
$A = 36$.

Answer:

36