Which one will replace the question mark ?

Final answer: 26

Pattern: the bottom number equals the sum of the squares of the two top numbers.

• Left figure: 2^2 + 4^2 = 4 + 16 = 20

• Middle figure: 3^2 + 9^2 = 9 + 81 = 90

• Right figure (find ?): 1^2 + 5^2 = 1 + 25 = 26

Therefore the missing number is 26.