<p>For z =&nbsp;<span class="equation">\(a^2x^3y^\frac{1}{2}\)</span>, where &#39;a&#39; is a constant. If&nbsp;percentage error in measurement of &#39;x&#39; and &#39;y&#39; are 4% and 12% respectively, then the percentage error for &#39;z&#39; will be_____%</p>