Correct ^^My formula for finding a cone is 3.14 × half of diameter squared × height ÷ 3 = answer. (I do this with a calculator, because if I didn't, it'd be wrong) I made up my own formula because I couldn't figure out their formula
Sometimes it helps if you understand how/why the formula works. I had a GREAT math teacher in high school, and that is how he taught us the various formulas for area, volume, etc.
Half the diameter is the radius. It's used in A LOT of formulas, and called "r." That 3.14 is pi, and anytime you have circles or spheres, you'll have pi involved. (I don't have the letter pi -- it's a Greek letter -- on my keyboard, so I have to spell it out.)
Pi x r squared is the area of the circle that is the base of the cone. Then you multiply by the height, and divide by 3, just like you wrote above. (I don't know why 3. I'm sure Mr. Richardson showed us, but I can't remember.)
Math has a language FULL of abbreviations, so that's why you get stuff that looks like hieroglyphs.
Volume of a pyramid is actually easier than a cone. No circles, no pi, no radius, no squaring. Multiply the width of the base by the length of the base. (That's the area of the base of the pyramid.) Now multiply that by the height. You have the volume of a solid box shape, square or rectangle, it doesn't matter. Divide by 3, because due to some math hocus-pocus, the pyramid is 1/3 the volume of that box. So that's why it's LxWxH/3.
I'm really showing my age, but there was a cartoon called "Pogo." One of the characters said, "Pie are not square! Pie are round! Cornbread are square!" I said that in math class and Mr. Richardson cracked up.