### Learning Targets:

I can explain that when a 3 dimensional figure is sliced it creates a confront that is two dimensional.I can snapshot different overcome sections that prisms and pyramids.

You are watching: Cross section of a rectangular pyramid

Describe each shape as precisely as girlfriend can. Click the applet and also drag the computer mouse to present the object turning in 3D.

Here space a rectangular prism and also a pyramid through the very same base and also same height. Drag the huge red point up and down to relocate the plane through the solids.

If we part each heavy parallel to its basic halfway up, what form cross sections would certainly we get? What is the same about the cross sections? What is different?

If we slice each heavy parallel to its base near the top, what shape cross sections would we get? What is the same about the overcome sections? What is different?

### Are you prepared for more?

Describe the cross sections that would result from slicing every solid perpendicular to its base.

Your teacher will offer you a set of cards. Kind the pictures into teams that make feeling to you. Be ready to describe your reasoning.

Use the applet to draw each cross section and also describe it in words.

Here is an applet through a rectangular prism, 4 devices by 2 systems by 3 units.

A airplane cuts the prism parallel come the bottom and also top faces.The aircraft moves up and cuts the prism at a various height.A vertical airplane cuts the prism diagonally.
A square pyramid has a base the is 4 units by 4 units. Its elevation is additionally 4 units.A airplane cuts the pyramid parallel to the base.A vertical airplane cuts the prism.
A cube has actually an edge of size 4.A aircraft cuts turn off the corner of the cube.The airplane moves farther indigenous the corner and makes a reduced through the middle of the cube.

## Lesson 11 Summary

When we slice a three-dimensional object, us expose brand-new faces that room two dimensional. The two-dimensional face is a cross section. Numerous different overcome sections are possible when slicing the same three-dimensional object.

Here space two peppers. One is sliced horizontally, and the various other is sliced vertically, producing different cross sections.

The imprints that the slices represent the two-dimensional faces developed by each slice.

It takes exercise imagining what the cross section of a three-dimensional object will certainly be for different slices. It help to experiment and also see for yourself what happens!

## Glossary Terms

cross section

A cross section is the brand-new face girlfriend see when you slice v a three-dimensional figure.

For example, if you slice a rectangular pyramid parallel come the base, you get a smaller rectangle together the overcome section.

## Lesson 11 practice Problems

A cube is reduced into 2 pieces by a single slice that passes through point out A , B , and C . What form is the cross section?

Describe exactly how to part the three-dimensional number to an outcome in each cross section.

Here are two three-dimensional figures.

Each row has the degree measures of two supplementary angles. Complete the table.

measure ofan anglemeasure ofits supplement
80^circ
25^circ
119^circ
x

Two months ago, the price, in dollars, of a cell phone was c .

Last month, the price of the phone increased by 10%. Write an expression for the price that the phone critical month.This month, the price the the phone reduced by 10%. Create an expression for the price that the phone this month.Is the price the the phone call this month the exact same as that was two months ago? explain your reasoning.

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