Answer:
The required foil is about 2l + lb sq units.
Step-by-step explanation:
Given:
A triangular prism covered with foil.
To Find:
If two ends are not covered how much foil is required.
Solution:
The triangular prism has total of 5 faces as
two side faces ............... Rectangular shape
one bottom face.............rectangular shape
two side faces............ triangular face.
(Refer the attachment for diagram)
Area of triangle = 1/2(base × height)
Now there 2 traingles so
Total are for triangle = base × height
Area for bottom rectangle,
=length *breadth = l * b
Area for 2 side rectangles,
=2*(length * breadth)
=2*(l*S)
=2 * l * S
Hence required area =total area -area of triangle
(As triangles are presented at both ends) and as per condition.
= (2ls + lb + bh) - bh
= 2ls + lb.
