The instrument in the geometry box having the shape of a triangle is called a
A) Protractor
B) Compasses
C) Divider
D) Set-Square

Hint: Geometry box can be defined as the set of basic equipment required for the regular use in the basic geometrical diagram and the graphs. It consists of the compass, ruler, divider and two set squares and the protractor. Here, we will understand all the given four options and then identify the correct option.

Complete step by step solution:
Protractor: Protractor can be defined as the measuring instrument which is typically made of transparent plastic or glass. They are typically half disc or semi-circle.
Compasses: compasses can also be defined as the pair of compasses which is the technical drawing instrument and used for circles or arcs. It has one pen or pencil point and the other sharp point which is joined at the top with the pivot.
Divider: Divider has two pointed legs joined at the top with the pivot. It is used to compare sizes, dividing line segments and measuring distances.
Set-square: Set square can be defined as the plastic or metal device which is shaped like a triangle (as shown below) and used for drawing straight lines and the angles.

Therefore, the instrument in the geometry box having the shape of the triangle is called set square.
Hence, from the given multiple choices the option (D) is the correct answer.

Note:
Do not get confused with the two terminologies compass and the divider. Essentially a compass is a divider in which one of the points is replaced with the pen or the pencil or any other marking devices.