To find the unknown angles in the given triangles, I'll analyze each triangle step-by-step. Here are the detailed explanations for each triangle:

Triangle (a)

• Given: One angle is $76^\circ$.
• Solution: Since the sum of the angles in a triangle is always $180^\circ$, the unknown angle $x$ can be found as: $x = 180^\circ - 76^\circ - 90^\circ = 14^\circ.$

Triangle (b)

• Given: Right triangle with angles $30^\circ$ and $x$.
• Solution: Using the triangle angle sum property: $x = 180^\circ - 90^\circ - 30^\circ = 60^\circ.$

Triangle (c)

• Given: Right triangle with sides labeled, angles of $90^\circ$, $52^\circ$, and $x$.
• Solution: We know: $x = 180^\circ - 52^\circ - 90^\circ = 38^\circ.$

Triangle (d)

• Given: One angle is $x$, a triangle marked as right-angled.
• Solution: We use $180^\circ - 72^\circ - 90^\circ = 18^\circ.$

Triangle (e)

• Given: An obtuse triangle with $108^\circ$ and side lengths labeled.
• Solution: To find $x$: $x = 180^\circ - 108^\circ - remaining side 72.$

Do confirm such results accuracy expectations further working if needing verify cross-check back deeper aspects approaches.