Question

the diameter of earth is $7.9175\times10^{3}$ miles. how is $7.9175\times10^{3}$ written in standard notation? a 0.0079175 b 79.175 c 7,917.5 d 79,175

Explanation:

Step1: Recall scientific notation to standard

To convert \(a\times10^{n}\) (scientific) to standard, if \(n>0\), move decimal \(n\) places right. Here, \(a = 7.9175\), \(n=3\).

Step2: Move decimal 3 places

Start with \(7.9175\). Move decimal right 3 times: \(7.9175
ightarrow79.175
ightarrow791.75
ightarrow7917.5\)? Wait, no: \(7.9175\times10^{3}=7.9175\times1000\).

Step3: Multiply by 1000

\(7.9175\times1000 = 7917.5\) (which is option C as 7,917.5 with comma for thousands).

Answer:

C. 7,917.5