Question

A child is creating a pyramid with building blocks. The top three levels include 4 blocks, 10 blocks, and 16 blocks. How many blocks would be needed for a pyramid 25 levels tall? Use complete sentences to explain how a sum of an arithmetic series was applied?

Answer 1

sum of an arithmetic series a = 5 d = 6 and n = 25

\[s _{25}=\frac{25}{2}[2\times4 +(25 -1)\times4]\]

I'll leave you to calculate the sum

Answer 2

oops a = 4

Answer 3

thank you