Answer:
B. 6
Detailed explanation:
<em>Alright, so using the Pythagorean theorem, </em>
<em> in this case, we have the "c" and "b" of the triangle. Therefor, we are looking for "a"</em>
<em>so, to solve the problem, simply begin by substituting what you already have:</em>

<em>Now that this is substituted, The next step is to go ahead and find the values after solving the exponents:</em>

<em>Now, we need to find the value of "a".</em>
<em>In this case, we are provided with 4 options and one of them has to be correct.</em>
<u><em>If "a"=12 then "a squared" would equal 144.</em></u>
<u><em>the statement 100=144+64 is </em></u><u><em>incorrect.</em></u>
<u><em>If "a"=6 then "a squared" would be 36.</em></u>
<em>The statement 100=36+64 is </em><em>correct.</em>
<em>
</em><u><em>If "a"=36 the "a squared" would be 1296.</em></u>
<u><em>The statement 100=1296+64 is </em></u><u><em>incorrect.</em></u>
<u><em>If "a"=18, then "a squared" would be 324.</em></u>
<u><em>The statement 100=324+64 is</em></u><u><em> incorrect.</em></u>
<u><em>Therefor, the answer is B.6</em></u>
<u><em></em></u>
Hope this helps ^-^