How many diagonals does a triangle have?

Name the type of the following triangles:

$\mathrm{\Delta PQR}, \angle \mathrm{P}=40°, \angle \mathrm{Q}=60°, \angle \mathrm{R}=80°$

Name the type of the following triangle:

$\mathrm{\Delta DEF}, \angle \mathrm{D}=90°, \mathrm{DE}=\mathrm{DF}=5 \mathrm{cm}$

(Right angled triangle/Right angled isosceles triangle)

What is the shape of a geometry box? Also find how many curved faces, flat faces, vertices, edges are there in a geometry box?

What is the shape of a cold drink can

Also find how many curved faces, flat faces, vertices, edges are there in each of these solids?

What is the shape of a bar of chocolate 

Also find how many curved faces, flat faces, vertices, edges are there in each of these solids?

What is the shape of a birthday cap.

Also find how many curved faces, flat faces, vertices, edges are there in each of these solids?