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Firefighting

publish date2025/10/25 04:40:18.545807 UTC

To fight a forest fire, the forestry department plans to clear a rectangular fire break around the fire, as shown in the following figure. Crews are equipped with mobile communications that have a 3,000-yard range. Can crews at points \( A \) and \( B \) remain in radio contact?

Diagram

\( c \) = (1)

Correct Answer

(1) 2600

Explanation

We will use the Pythagorean theorem to find the distance between points \( A \) and \( B \).  If the distance is less than 3,000 yards, the crews can communicate by radio.  If it is greater than 3,000 yards, they cannot.

The line segments connecting points \( A \), \( B \), and \( C \) form a right triangle.  To find the distance \( c \) from \( A \) point to point \( B \), we can use the Pythagorean equation, substituting 2,400 for \( a \) and 1,000 for \( b \) and solving for \( c \).

This is the Pythagorean equation

\[ a^2 + b^2 = c^2 \]Substitute for \( a \) and \( b \)

\[ \require{color} \color{red}{2,400^2} + \color{blue}{1,000^2}=c^2 \]Evaluate each exponential expression

\[ 5,760,000 + 1,000,000 = c^2 \]Do the addition

\[ 6,760,000=c^2 \]Reverse the sides of the equation so that \( c^2 \) is on the left

\[ c^2=6,760,000 \]If \( c^2 \) = 6,760,000, then \( c \) must be a square root of 6,760,000.  Because \( c \) represents a length, it must be the positive square root of 6,760,000.

\[ c= \sqrt{6,760,000} \]Use a calculator to find the square root.

\[ c=2,600 \]The two crews are 2,600 yards apart.  Because this distance is less than the 3,000 yard range of the radios, then can communicate by radio.

Reference

Mathematics for college students, go-math-science.com