The diagram below shows a plane slicing a rectangular prism along the diagonals of its side faces. The shaded figure shows the cross section obtained. Which is closest to the area of the cross section?

28 square inches

36 square inches

7 square inches

12 square inches

Question

The diagram below shows a plane slicing a rectangular prism along the diagonals of its side faces. The shaded figure shows the cross section obtained. Which is closest to the area of the cross section?

 28 square inches

 36 square inches

 7 square inches

 12 square inches

hang254 · Answer

attachment

allank · Answer

Hint: the shaded area has a length of 5inches and width that is a hypotenuse of a right-angled triangle.

hang254 · Answer

The hypotenuse is 7.2

hang254 · Answer

@allank

allank · Answer

Yes

hang254 · Answer

i got 12, is that correct?

allank · Answer

Uuh, I don't think so. Area=length*width
length = 7.2
width = 5

hang254 · Answer

but for triangular prism, isn't it area = 1/2 (bh)

allank · Answer

I may be wrong, but doesn't the question say rectangular prism?

hang254 · Answer

yes, but its talking about the triangular prism

hang254 · Answer

shaded region

allank · Answer

Maybe we aren't agreeing on something here. 
Do you agree that that figure is a cuboid (rectangular prism), with a rectangular plane slicing it into two halves?

allank · Answer

Wait a sec...my bad. Yeah, we are looking for the area of the triangular cross section..

allank · Answer

yeah, 12 is the answer. sorry =)

hang254 · Answer

Ok, thanks for your help!

allank · Answer

You're welcome :)