Find the missing angle in each irregular polygon using the formula (n-2) × 180°.

To find the missing angle $x$ in each polygon, we use the formula for the sum of interior angles:
$$ \text{Sum} = (n - 2) \times 180^\circ $$
where $n$ is the number of sides. We calculate the total sum, add up the known angles, and subtract that total from the sum to find $x$.

Here are the step-by-step solutions for each shape:

(a) Quadrilateral ($n=4$)
* Sum of angles: $(4-2) \times 180^\circ = 360^\circ$
* Known angles: $70^\circ + 88^\circ + 45^\circ = 203^\circ$
* Missing angle $x$: $360^\circ - 203^\circ = \mathbf{157^\circ}$

(b) Pentagon ($n=5$)
* Sum of angles: $(5-2) \times 180^\circ = 540^\circ$
* Known angles: $84^\circ + 153^\circ + 131^\circ + 105^\circ = 473^\circ$
* Missing angle $x$: $540^\circ - 473^\circ = \mathbf{67^\circ}$

(c) Hexagon ($n=6$)
* Sum of angles: $(6-2) \times 180^\circ = 720^\circ$
* Known angles: $120^\circ + 130^\circ + 100^\circ + 135^\circ + 110^\circ = 595^\circ$
* Missing angle $x$: $720^\circ - 595^\circ = \mathbf{125^\circ}$

(d) Pentagon ($n=5$)
* Sum of angles: $(5-2) \times 180^\circ = 540^\circ$
* Known angles: The square symbols represent $90^\circ$. So, $90^\circ + 90^\circ + 90^\circ + 143^\circ = 413^\circ$
* Missing angle $x$: $540^\circ - 413^\circ = \mathbf{127^\circ}$

(e) Heptagon ($n=7$)
* Sum of angles: $(7-2) \times 180^\circ = 900^\circ$
* Known angles: $96^\circ + 105^\circ + 161^\circ + 123^\circ + 155^\circ + 114^\circ = 754^\circ$
* Missing angle $x$: $900^\circ - 754^\circ = \mathbf{146^\circ}$

(f) Hexagon ($n=6$)
* Sum of angles: $(6-2) \times 180^\circ = 720^\circ$
* Known angles: $150^\circ + 127^\circ + 40^\circ + 202^\circ + 90^\circ (\text{square symbol}) = 609^\circ$
* Missing angle $x$: $720^\circ - 609^\circ = \mathbf{111^\circ}$

(g) Pentagon ($n=5$)
* Sum of angles: $(5-2) \times 180^\circ = 540^\circ$
* Known angles: $158^\circ + 112^\circ + 99^\circ + 99^\circ = 468^\circ$
* Missing angle $x$: $540^\circ - 468^\circ = \mathbf{72^\circ}$

(h) Octagon ($n=8$)
* Sum of angles: $(8-2) \times 180^\circ = 1080^\circ$
* Known angles: $140^\circ + 130^\circ + 100^\circ + 80^\circ + 280^\circ (\text{reflex}) + 110^\circ + 110^\circ = 950^\circ$
* Missing angle $x$: $1080^\circ - 950^\circ = \mathbf{130^\circ}$

(i) Quadrilateral ($n=4$)
* Sum of angles: $(4-2) \times 180^\circ = 360^\circ$
* Known angles: $90^\circ + 90^\circ + 43^\circ + 272^\circ (\text{reflex}) = 495^\circ$. *Wait, this sum exceeds 360. Let's look closer.*
* Actually, usually in these problems, if a reflex angle is given inside, it's part of the sum. But $495 > 360$. Let's re-read the diagram.
* Ah, the angle marked $272^\circ$ is the reflex angle at the "indentation". The interior angle of the polygon at that vertex is actually $360^\circ - 272^\circ = 88^\circ$.
* Let's recalculate using the interior angle $88^\circ$:
* Known interior angles: $90^\circ + 90^\circ + 43^\circ + 88^\circ = 311^\circ$
* Missing angle $x$: $360^\circ - 311^\circ = \mathbf{49^\circ}$? This is not in the options.
* Let's try another interpretation. Maybe the shape is treated as having 5 vertices if we count the indentation? No, it has 4 main corners plus the indent. It's a non-convex quadrilateral.
* Let's check the options again. 45, 80, 130, 157, 136, 125, 72, 111, 125, 146, 67, 127.
* Let's re-examine image (i). It looks like a rectangle with a triangle cut out. Vertices: Top-left ($90^\circ$), Top-right ($90^\circ$), Bottom-left ($43^\circ$), Indent ($272^\circ$ reflex?), Bottom-right ($x$).
* If we sum the interior angles directly: $90 + 90 + 43 + x + (360-272) = 360$?
* $223 + x + 88 = 360 \rightarrow 311 + x = 360 \rightarrow x = 49$. Still not an option.
* Let's look at the shape again. Is it possible the $272^\circ$ is NOT an interior angle but the exterior? No, it's drawn inside.
* Let's look at the other option: Maybe the polygon is considered to have 5 sides? (Top, Right, Bottom-Right segment, Bottom-Left segment, Left). If $n=5$, Sum = 540.
* Angles: $90, 90, 43, x, 272$. Sum = $495 + x = 540 \rightarrow x = 45$.
* Yes, 45 is in the options. So we treat the indentation as a vertex, making it a pentagon ($n=5$).
* Missing angle $x$: $\mathbf{45^\circ}$

(j) Hexagon ($n=6$)
* Sum of angles: $(6-2) \times 180^\circ = 720^\circ$
* Known angles: $101^\circ + 154^\circ + 72^\circ + 123^\circ + 145^\circ = 595^\circ$
* Missing angle $x$: $720^\circ - 595^\circ = \mathbf{125^\circ}$

(k) Hexagon ($n=6$)
* Sum of angles: $(6-2) \times 180^\circ = 720^\circ$
* Known angles: $160^\circ + 90^\circ + 90^\circ + 120^\circ + 124^\circ = 584^\circ$
* Missing angle $x$: $720^\circ - 584^\circ = \mathbf{136^\circ}$

(l) Pentagon ($n=5$)
* Sum of angles: $(5-2) \times 180^\circ = 540^\circ$
* Known angles: $136^\circ + 108^\circ + 76^\circ + 140^\circ = 460^\circ$
* Missing angle $x$: $540^\circ - 460^\circ = \mathbf{80^\circ}$

Final Answer:
(a) 157
(b) 67
(c) 125
(d) 127
(e) 146
(f) 111
(g) 72
(h) 130
(i) 45
(j) 125
(k) 136
(l) 80