Square of 30
30 squared equals 900. Squares appear in area calculations, the Pythagorean theorem, and statistics (variance uses squared distances).
Squares obey quiet rules. Divided by 9, a square only ever leaves 0, 1, 4 or 7 — 0 here. On the last digit, squares end only in 0, 1, 4, 5, 6 or 9, and 0 fits. Between its neighbors, 841 sits 59 below and 961 sits 61 above — the square ladder widens by exactly two at every step. Double the base and the square quadruples: 60² = 3600, which is 4 × 900. Two anchors most worth memorizing in this range are 12² = 144 and 15² = 225 — the odd-step rule above is why knowing them pays off, because from any anchor the next square is one step along this page's ladder.
| Expression | Value |
|---|---|
| 30² | 900 |
Frequently asked questions
What is 30 squared?
30 squared is 900, because 30 × 30 = 900. The exponent 2 is why it is written 30².
What is 31 squared, next to 30²?
31² = 961, which is 61 more than 30² = 900. Each step up adds double the base plus one.
Where do squares show up in real problems?
Area of a square with side 30, distance in the Pythagorean theorem, and variance in statistics all use squared values.