The base of the pyramid is the triangle on the very bottom. The formula for the area of a triangle is A = 1/2 x base x height.
In this triangle, the base length is 6 cm and the height is 7 cm, as shown clearly in the image. Using the formula for the area, we can easily solve for the area of this triangle.
A = 1/2 x 6 x 7
A = 1/2 x 42
A = 21 cm^2
Hope this helps! :)
