An archeologist was digging around the pyramids of ancient Egypt. He discovered a mummie covered in chocolate and nuts.
On further investigation the mummie was identified as pharaoh roche.
This is the clue to our topic.
We are going to look at the surface area of pyramids here.
Surface area is the area of each face of the pyramid added together.
Before we are ready to go there are a few things to remember:
Area of a square = base x height
Area of a rectangle = base x height
Area of a triangle = base x height ÷ 2
This pyramid has a side length of 4 cm and it's height is 5 cm.
To find the surface area of this square based pyramid we
1. Calculate the area of the base 4 x 4 = 16 cm²
2. Find the area of one of the triangular sides 4 x 5 ÷ 2 = 10 cm²
3. There are four sides to the pyramid so 10 x 4 = 40 cm²
4. Add the total area of the sides to the area of the base = 16 + 40 = 56 cm²
This triangular based pyramid has base 6 cm height 8 cm
To find the surface area of this triangular based pyramid we
1. Calculate the area of the base 6 x 8 ÷ 2 = 24 cm²
2. There are four sides to the pyramid (the base and three sides) so 24 x 4 = 96 cm²
The sides base has sides of 5 cm and 6 cm. The height of the pyramid 6 cm.
To find the surface area of this rectangular based pyramid we
1. Calculate the area of the base 5 x 6 = 30 cm²
2. We find the area of the triangle with the base of 5 cm, 5 x 6 ÷ 2 = 15 cm²
3. The face opposite has the same area so multiply by 2. 15 x 2 = 30 cm²
4. Now find the area of the triangle with the base of 6 cm. 6 x 6 ÷ 2 = 18 cm²
5. The face opposite has the same area so multiply by 2. 18 x 2 = 36 cm²
6. Finally add all your answers together 30 + 30 + 36 = 96 cm²
Where do Pharaoh's like to eat?
Hopefully, this has made you smile as you start the activity.