From the image you provided, it appears that we have a quadrilateral with the following angles labeled:

• Top-left corner: $70^\circ$
• Top-right corner: $110^\circ$
• Bottom-right corner: $100^\circ$
• Bottom-left corner: an unknown angle, which we will label as $X^\circ$

In a quadrilateral, the sum of the interior angles is always $360^\circ$. We can use this property to solve for the unknown angle $X$.

The equation for the sum of the angles is: $70^\circ + 110^\circ + 100^\circ + X = 360^\circ$

Now, let's solve for $X$: $280^\circ + X = 360^\circ$ $X = 360^\circ - 280^\circ$ $X = 80^\circ$

So, the unknown angle $X = 80^\circ$.

Would you like further details or have any other questions?

Here are 5 related questions to expand your understanding:

1. How do you calculate the sum of interior angles for any polygon?
2. What would the angles sum be for a pentagon?
3. How do you determine if a quadrilateral is convex or concave based on its angles?
4. Can you apply the angle sum property to irregular quadrilaterals?
5. What happens to the sum of angles in non-Euclidean geometry?

Tip: Always remember that in any polygon, the sum of the interior angles depends on the number of sides. For a polygon with $n$ sides, the sum of interior angles is $(n - 2) \times 180^\circ$.