What is big and 4 inches and black? a) My phone b) white board eraser c) bluetooth speaker

A) your phone

Step-by-step explanation:

It could be you BT speaker but that depends on what size your talking about.

Also it depends what phone model you have a lot of phone are 5 inches

but in the end my answer is A

a net is a diagram that shows a “flattened” view of a solid. in a net, each face and base is shown with all of its dimensions. a net can also serve as a pattern to build a three-dimensional solid.

a pyramid is a three-dimensional object with a base that is a polygon and triangular faces that meet at one vertex.

" the net of a triangular pyramid consists of four triangles. the base here we are given of the pyramid is a equilateral   triangle, and the lateral faces are also triangles "