How many cubes are needed to build the base of this structure

5 cubes

Step-by-step explanation:

The figure consists of three layers.

The top layer consists of one cube (this cube is visible).

The second layer consists of 3 cubes (two of them are visible and one is not visible - placed under the cube of the top layer).

The third layer (base layer) consists of 5 cubes:

So, 5 cubes are needed to build the base of the figure.

he sells x mount because thats eqivilqant to the maz and then divided into quarters

step-by-step explanation:

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4