Question

sonar sonar is used by oceanographers to locate marine animals and to map the contours of the ocean floor. sonar sends out sound pulses, called pings, and receives the returning sound echo. sonar uses the returning sound echo to detect the location of animals or the distance from a rock formation. if each unit on the coordinate grid measures 1 mile, what area does the sonar system cover? round to the nearest tenth.

Explanation:

Step1: Identify the shape

The sonar - covered area is a circle.

Step2: Determine the radius

By observing the grid, the radius $r$ of the circle is 5 miles (counting the number of grid - units from the center to the edge of the circle).

Step3: Use the area formula for a circle

The formula for the area of a circle is $A=\pi r^{2}$. Substitute $r = 5$ into the formula: $A=\pi\times5^{2}=25\pi$.

Step4: Calculate and round

$A = 25\pi\approx25\times3.14159 = 78.53975\approx78.5$ square miles.

Answer:

$78.5$ square miles