+33615 If it's a right-angled triangle the sum of the squares of the two shorter sides will equal the square of the longest side (Pythagoras).
$${{\mathtt{7}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{9}}}^{{\mathtt{2}}} = {\mathtt{130}}$$
$${{\mathtt{15}}}^{{\mathtt{2}}} = {\mathtt{225}}$$
So, clearly not a right-angled triangle
.
+33615 If it's a right-angled triangle the sum of the squares of the two shorter sides will equal the square of the longest side (Pythagoras).
$${{\mathtt{7}}}^{{\mathtt{2}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{9}}}^{{\mathtt{2}}} = {\mathtt{130}}$$
$${{\mathtt{15}}}^{{\mathtt{2}}} = {\mathtt{225}}$$
So, clearly not a right-angled triangle
.
