Mathematics Magazine for Grades 1-12  

Grade 7

Theory

Surface Area of Rectangular Prisms

A rectangular prism has 2 ends and 4 sides. Opposite sides have the same area. The surface area is the sum of the areas of all six sides.

How to find the surface area of Rectangular Prisms:

Find the area of two sides (Length Height) 2 sides

Find the area of adjacent sides (Width Height) 2 sides

Find the area of ends (Length Width) 2 ends

Add the three areas together to find the surface area

Example:

The surface area of a rectangular prism 5 cm long, 3 cm. wide and 2 cm. high = 5 2 2 + 3 2 2 + 5 3 2 = 20 + 12 + 30 = 62 cm².

Solutions from the Previous Issue:

Complete the simple interest table. Round to the nearest cent.

Simple Interest formula

I = P x r x t

I – the interest

P – the principal amount

r is the interest rate 5 per year or in decimal formula/100

t –is the time involved, 0…year(s) time periods

Proposed Exercises:

Calculate:   

1 =      

2   =

3 =

4   =

5 = 

   =