Thursday, May 3, 2012

Chapter 12 and 13 Prisms, Cylinders, Pyramids, and Cones

Prisms: SA= 2B + Ph
V= Bh
Cylinders: SA= 2(pi x r squared) + (2 x pi x r)h
V= pi x r squared x h
Pyramids: SA= B + 1/2Pl or SA= B + LA (LA= 1/2Pl)
V= 1/3Bh or V= Bh/3
Cones: SA= pi x r squared + LA (LA= pi x r x l)
V= 1/3 x pi x r squared x h or V= pi x r squared x h/3 

The formulas for these shapes can be looked at differently by its many qualities. First of all, each formula for volume involves finding the area of the base of the object. Both cylinders and cones use pi because their bases are circles; but, any shape that does not contain a circle will not need to use pi in its formula. To find the volume of cones and pyramids, one must multiply by one-third to find it because each shape is a third of the prism or the cylinder. Also all of the formulas use slant height for cones and pyramids. Finally, the formulas are different because each has to change referring to the different angles of the shapes; for instance, since the bases of cones and cylinders are circles, their surface area and volume measurements will not be exactly right. That's because pi is never-ending (This does not apply to prisms or pyramids because they are not involved with circles). These are only some similarities and differences between the shapes and the formulas.

Wednesday, April 18, 2012

4-18-12 Homework

What are the formulas for area of a rectangle, squaare, and parallelogram?
The formula for all 3 of these shapes is Length X Width

Find the dimensions of Tennessee?
The length of Tennessee is 440 miles and the width is 120 miles.

Compare the actual area.
The approximated area of Tennessee is 52800 square miles.

Tuesday, April 10, 2012

4-9-12 homework

In chapter 10, I learned things about a circle that i never knew before and really surprised me. I already knew about a chord, diameter, and a radius. But in this chapter I have learned what an arc, secant, and tangent are. I also learned different kinds of angles that I will work with for my whole life. Also, architects are going to use different angles to make up different shapes to use in a structure. the one question i have is how can you identify what i secant is?