Geometry: Perimeter of Rectangles: TEAS Practice Question with Answer & Explanation

Understanding Perimeter Calculation

To solve this problem, you must understand the geometric concept of perimeter. While the ATI TEAS often includes complex word problems, many are simple applications of standard geometric formulas.

The perimeter is the total distance around the outside of a two-dimensional shape. For a rectangle, we have two equal lengths ($l$) and two equal widths ($w$).

The Step-by-Step Calculation

1. Identify the Formula: The formula for the perimeter ($P$) of a rectangle is:

   • $P = 2l + 2w$
   • Alternative: $P = 2(l + w)$

2. Plug in the Values: Our mobile health clinic area has a length ($l$) of 40 feet and a width ($w$) of 20 feet.

   • $P = 2(40) + 2(20)$

3. Perform the Math:

   • $2 \times 40 = 80$
   • $2 \times 20 = 40$
   • $80 + 40 = 120$

The total perimeter is 120 feet.

Analysis of Incorrect Answers

• A) 48 feet: This error often occurs if a student attempts to multiply $24 \times 2$ or makes a significant addition error. It does not correlate with the dimensions provided.
• B) 60 feet: This is the result of adding the length and width only once ($40 + 20 = 60$). Remember, a rectangle has four sides; you must account for all of them!
• D) 800 feet: This represents the area of the rectangle ($40 \times 20 = 800$). On the TEAS, always double-check if the question asks for "area" (square units) or "perimeter" (linear units).

Nursing Context: Why This Matters

As a nurse, you may need to calculate the perimeter of a wound or the space required for medical equipment. Accurate measurement is a fundamental skill for charting and patient safety.

Memory Tip

Think of the word PE-RIM-ETER. The word contains "RIM." The perimeter is the measurement of the rim (the outside edge) of the shape. Unlike area, which fills the inside, the perimeter just walks the line around the edge.