Question

a. undecagon (11 sides):
b. dodecagon (12 sides):
c. chiliagon (1000 sides):

Explanation:

Step1: Sum formula for interior angles

Sum = $(n-2) \times 180^\circ$, where $n$ is the number of sides.

Step2: Undecagon (n=11)

Sum = $(11-2) \times 180^\circ = 9 \times 180^\circ = 1620^\circ$

Step3: Dodecagon (n=12)

Sum = $(12-2) \times 180^\circ = 10 \times 180^\circ = 1800^\circ$

Step4: Chiliagon (n=1000)

Sum = $(1000-2) \times 180^\circ = 998 \times 180^\circ = 179640^\circ$

Answer:

a. 1620°
b. 1800°
c. 179640°