*If you need me to do #5, DM me!
3. The area of a triangle can be given by (just plug and chug as always):

The area of the triangle is
6ft².
4. I will divide into a triangle and a rectangle (because the actual equation for the area of a pentagon requires it to be a perfect pentagon). Let's do the triangle first (height is 3 because you subtract 12 from 15):


Now we just add them:

So, the area of that pentagon is
108m².
5. You are actually wrong on this one because the area of a triangle is:

So, just halve your answer and it will be correct.
6. We can just split it into 4 triangles of equal area and then multiply the area of 1 triangle by 4 to get the total area. Let's do just that:

Multiply by 4 to get total area:

So, the area of the given rhombus is
25cm².
We immediately note that 3 and 9 are multiples. Therefore, they are factorable. 9 goes into 3 three times, and 3 goes into three 1 time. Therefore, we can take out three from the whole expression to get 3(c - 3).
Answer:
15.8
Step-by-step explanation:
First we need to round to the nearest tenth.
18.134 rounds to 18.1 (since it's closer to 18.1 than 18.2)
2.28 rounds to 2.3 (since it's closer to 2.3 than 2.2)
Then we subtract
18.1-2.3=15.8
In this item, we are given that the length of the rectangle is equal to 80% of its width and that its width is equal to 95 inches. The length can be calculated by multiplying the decimal equivalent of the given percentage and the width. That is,
l = 0.8w
If we are to substitute the given value,
l = 0.8(95 inches) = 76 inches
Hence, the answer is that the length is 76 inches.