To solve the problem, we need to determine the length of side $BC$ of the rectangle.

Step 1: Coordinates of Points

From the image:

• Point $B = (8, 9)$
• Point $C = (8, 4)$

Step 2: Calculate Distance

Side $BC$ is vertical, so the length is the difference in the $y$-coordinates: $\text{Length of } BC = |y_2 - y_1| = |4 - 9| = 5$

Final Answer:

The length of side $BC$ is 5.

Would you like a detailed explanation or help with similar problems?

5 Related Questions:

1. How can you calculate the length of a diagonal of a rectangle given the vertices?
2. What formula is used to calculate distances between points in 2D space?
3. How do you identify the lengths of horizontal and vertical sides in a rectangle?
4. What is the importance of absolute values in measuring lengths?
5. Can you use the Pythagorean theorem to solve for distances in rectangles?

Tip:

When dealing with vertical or horizontal lines, only one coordinate changes. Use the distance formula sparingly—direct subtraction of coordinates often suffices!