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Find the circumference and the area Of the circle with diameter 4yd

Use vale 3.14 to help with answer
Be specific with answers with right symbol Yd , Yd2 or Yd3

User Nbalas
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1 Answer

4 votes

Answer:

  • circumference: 12.56 yd
  • area: 12.56 yd²

Explanation:

The formula for circumference is ...

C = πd

C = (3.14)(4 yd) = 12.56 yd . . . . . . . . fill in the numbers; do the arithmetic

The circumference is 12.56 yd.

__

Since the diameter is 4 yd, the radius is half that, or 2 yd. The formula for the area is ...

A = πr²

Fill in the numbers and do the arithmetic.

A = (3.14)(2 yd)² = 12.56 yd²

The area is 12.56 yd².

_____

Comment on units

In problems such as these, I find it is often useful to keep the units with the numbers. The units can be treated like any variable: multiplied, divided, measures combined by addition or subtraction of "like units".

Just as (2a)² = 2²·a² = 4a², so does (2 yd)² = 2²·yd² = 4 yd². You can be sure that if the units of the problem don't make sense, there is an error somewhere.

User Louis W
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