# Math questions...?????

Ok... this is mostly about perimeter/area... surface area/volume

1.Say, if you have a composite figure that has a rectange and a SEMI CIRCLE attached to it, the area formula of a circle is (3.14 times radius squared... Divided by 2).... so if I see a semi circle, do I have to divide it by 2 another time?? Ik if I see a whole circle, I don't divide it by 2.

2. Say, if you have a composite figure that has a rectange and 2 TRIANGLES attached to it..If i found out the area of 1 TRIANGLE... do I need to divide it by 2 to get the second triangle instead of rewriting the formula again??

3. Lucinda says that the volume of her lunch bag is 1200 cm cubed. Could this be right? Explain specificly plzz!

4. Find the dimensions of a rectangular yard of maximum area that can be enclosed with 68 m of fencing.

5. For fractions, if I needa add a mixed number and another mixed number... I need to find a common denominator right? What if it has none? Like 3 times 2 is 6. What if 2 denominators can't go in each other? Do I needa find the least common demoninator by dividing both sides by the less to get the same denominator?? If you get what Im saying...

Well thats it!!! Plzz help, exam tmr!

### 1 Answer

- Anonymous8 years agoFavorite Answer
Area of a circle = pi r^2 ----> Area of a semi circle = (pi r^2)/2