#### Answer

$a_1=1$
$a_2=\frac{1}{4}$
$a_3=\frac{1}{9}$
$a_4=\frac{1}{16}$
$a_{100}=\frac{1}{10000}$

#### Work Step by Step

We are given:
$a_{n}= \frac{1}{n^{2}}$
We evaluate:
$a_1= \frac{1}{(1)^{2}}=1$
$a_2= \frac{1}{(2)^{2}}=\frac{1}{4}$
$a_3= \frac{1}{(3)^{2}}=\frac{1}{9}$
$a_4= \frac{1}{(4)^{2}}=\frac{1}{16}$
$a_{100}= \frac{1}{(100)^{2}}=\frac{1}{10000}$