Question

show what you know! which expression is in correct scientific notation? 4.5×100 0.45×10³ 4.5×10² 45×10¹

Explanation:

Step1: Recall scientific - notation rule

Scientific notation is of the form $a\times10^{n}$, where $1\leqslant|a|\lt10$ and $n$ is an integer.

Step2: Analyze each option

• For $4.5\times100 = 4.5\times10^{2}$, but $100$ is not in the correct power - of - 10 form for scientific notation.
• For $0.45\times10^{3}$, since $0.45\lt1$, it is not in correct scientific notation.
• For $4.5\times10^{2}$, $a = 4.5$ ($1\leqslant4.5\lt10$) and $n = 2$ (an integer), so it is in correct scientific notation.
• For $45\times10^{1}$, since $45\geqslant10$, it is not in correct scientific notation.

Answer:

$4.5\times10^{2}$