Answer:

Step-by-step explanation:
First consider the diagram:
Now, we know that

Now, the area of the triangle ABC is given by,

Step-by-step explanation:
Geometry is in maths
Geology is in geography..
I hope you understand..
Answer:
C. 17.9
Step-by-step explanation:
First you have to find the area of the circle, to then subtract it from the area of the square around it.
To get the area of the circle you must take the radius(half of the diameter) and square it. 3^2 is 9. Then you mutiply that by Pi( 3.14). Which is 7.07.
Next you have to subtract that from the area of the square deck.
25-7.07=17.9
Well hello again :3. This is also quite simple. The diameter of a circle is 2 times the radius. So we can refit this into the equation and say that our new formula using diameter is

. Now we can say that 10/2 is 5 and

is 25. Therefore your answer is

or 78.54.