When I saw this, I said to myself "Self ! We don't know anything about
decagons.", and then I went searching online for stuff about decagons.
This just goes to show how stupid I can be when I don't take a little time
to THINK before I go running around screaming.
-- When you draw all the lines from the center to the vertices of the
decagon, you'll have 10 little triangles.
-- The area of the whole thing is 161 square inches, so the area of each
little triangle is 1/10 of that . . . . . <em>16.1 square inches</em>.
-- The area of each little triangle is (1/2) (base) (height), just like
every other triangle.
The base is the 4.6 inches of one side of the decagon.
Area = (1/2) (base) (height)
Multiply each side by 2: 2 x area = (base) x (height)
Divide each side by (base): (2 x area) / (base) = height
Height = (2 x 16.1) / (4.6) = <em>7 inches</em> .
Let that be a lesson to both of us.
THINK before you jump.
Answer:
c
Step-by-step explanation:
because x=9
Answer:

Step-by-step explanation:
9 = −1 + 4a
+ 1 + 1
_________
![\displaystyle \frac{10}{4} = \frac{4a}{4} \\ \\ 2\frac{1}{2} = a \\ \\ \\ 3[2\frac{1}{2}] + 4[2\frac{1}{2}] + 9 + 5 = 7\frac{1}{2} + 10 + 9 + 5 = 31\frac{1}{2}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7B10%7D%7B4%7D%20%3D%20%5Cfrac%7B4a%7D%7B4%7D%20%5C%5C%20%5C%5C%202%5Cfrac%7B1%7D%7B2%7D%20%3D%20a%20%5C%5C%20%5C%5C%20%5C%5C%203%5B2%5Cfrac%7B1%7D%7B2%7D%5D%20%2B%204%5B2%5Cfrac%7B1%7D%7B2%7D%5D%20%2B%209%20%2B%205%20%3D%207%5Cfrac%7B1%7D%7B2%7D%20%2B%2010%20%2B%209%20%2B%205%20%3D%2031%5Cfrac%7B1%7D%7B2%7D)
I am joyous to assist you anytime.