If all angles are 90 degrees, and the crystal has a square base with a height that is larger than one of the square sides, what type of unit cell is it

Tetragonal unit cell.

Step-by-step explanation:

A unit cell is the smallest part of a material which is formed by a well arranged lattice points. Some common types are; face centered, body center, tetragonal, cubic etc

Tetragonal unit cell has a square top and base, with rectangular sides. The internal angles are each, and consists of molecules, atoms, or ions (lattice points) arranged at each corners of the unit cell.

The crystal as described in the given question is a tetragonal unit cell.

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl