4 yd
What is the diameter?

4

Step-by-step explanation:

   circumference: 12.56 yd

   area: 12.56 yd²

Step-by-step 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.

sas (side angle side)

aa(angle angle)

sss(side side side)

sas you have to find two sides with an angle in between

aa you find two angles because it will always add up to 180

sss find all sides

step-by-step explanation:

i agree because i see the other persons thinking is clear