# Video: Determining the Rectangle Resulting from Slicing a Triangular Prism

Determine the two-dimensional figure that results from slicing the given three-dimensional shape as shown. [A] Figure A [B] Figure B [C] Figure C [D] Figure D [E] Figure E

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### Video Transcript

Determine the two-dimensional figure that results from slicing the given three-dimensional shape as shown.

So, here we have a three-dimensional shape, a triangular prism, which is sliced by this blue card. So, what we need to do is figure out if we took away the front section, then what 2D shape would be left exposed behind the card. Since we have a prism, this means that the depth of our shape will be constant. So, in our two-dimensional shape, this means that the length of the top and the base will be the same size.

In our 3D prism, the height of our triangle stays constant throughout. Meaning that both the vertical lengths in our two-dimensional shape will be the same size. If we look at the upper face on our three-dimensional shape, all of the angles here will be right angles. So, the same will be true in our two-dimensional shape. Let’s now visualise this shape if we look at it from a different view.

The part of this shape that’s shaded in green will correspond to the top face in our three-dimensional shape. Let’s remind ourselves that we established that the top length and the base length in our two-dimensional shape are the same length, and also that our two vertical lengths are the same size. And we also have four right angles. So, our answer then must be option C, a rectangle.