Answer:
3.451, 3.452, 3.453, 3.454, 3.455, 3.456, 3.457, 3.458, 3.459, 3.460
"Perimeter" is the distance all the way around the drawing. If the drawing has sides, then the perimeter is the SUM of the lengths of all the sides. It's exactly the distance an ant would have to walk along the line, to get all the way around to where he started from.
To get the perimeter of the triangle, you have to add up the lengths of the three sides.
(2a - 3) + (2a) + (3a + 1) =
2a - 3 + 2a + 3a + 1 .
Add up all the 'a's: 2a + 2a + 3a = 7a
Add up all the just plain numbers: -3 + 1 = -2
Write them together, as a binomial: 7a - 2
THAT's your expression for the perimeter.
The standard form of a circle is:

Your center is
and your radius is 
Plug them into the equation and you get


The correct answer is D.
Answer:
12 feet
Step-by-step explanation:
Sometimes, a simple drawing is a great way to start! In the attached drawing, the red line represents the ladder, the brown represents the ground, and the black represents the building!
We want to find the side of the triangle from where the ladder meets the building to where the building meets the ground. This can be found using trigonometric identities, namely sine:

Plug in known values:

Rearrange to isolate the variable:

Simplify!

Round to the nearest foot:
