Algebraic Expressions: square meters in circle w/ d = 25 m

[angel716]

Crop circles. The expression r2 gives the area of a circle with radius r. How many square meters of wheat were destroyed when an alien ship made a crop circle of diameter 25 meters in the wheat field at the Southwind Ranch? Round to the nearest tenth. Find  on your calculator.

for the life of me I haven't done math in like 5 1/2 years and this questions is killing me the example in my text book is awful i need this broken down into english

 

[matt000r000]

Re: Algebraic Expressions

does the litle box stand for pi? it probably does. also, the formula for the area of a circle is pi time the radius to the power of 2, or (pi)r^2. thats probably what you meant. pi is about 3.14. so there's the answer to the seccond part of the question. then, replace "r" in the equation with 25 and solve. be sure to bring 25 to the power of 2 before multiplying by pi.

 

[angel716]

Re: Algebraic Expressions

yes that little thing is suppose to be pi so would i times 25 by pi and get the answer?

 

[stapel]

The area A of a circle with radius r is given by A = (pi)(r^2).

You are given that the diameter d is 25. What then is the radius? Plug this value into the area formula.

:wink: