864 is 40% of what number

'is' in mathematics means equal

'of' in mathematics means multiplication

Translating 864 is 40% of what number into an equation, we get:

864 = 40% * x

40%, or 40 percent, is nothing but 40 over 100 or 40/100, which is the same as 2/5.

864 = 2/5 * x

Multiply 5 on both sides.

864 * 5 = 2/5 * 5 * x

4320 = 2x

Divide 2 on both sides

4320/2 = 2x/2

2160 = x

x = 2160

864 is 40% of 2160.