<p>
</p>
<p>One would think so, Bovertine, but things that might appear crystal clear to you (and to someone such as Fignewton) seem to frustrate many students. Fwiw, while the 3-4-5 rules are well-known, the ability of recognize the patterns when NOT given is much rarer. In this case, please note that students are only given the two segments 9 and 16. </p>
<p>The altitude 12 is obviously found through 9/x = x/16 or x^2 = 144.</p>