Given the number 321.51, to express it in standard form, we use the general standard form as reference:
[tex]A\cdot10^n[/tex]Where A is a number less than 10 and greater than or equal to 1. For this problem, A should be 3.2151, and because we move the decimal point two places to the left, we need to multiply it by 100 = 10² to get 321.51. Then:
[tex]321.51\to3.2151\cdot10^2[/tex]