The polygon in option 3 is not octagon at all, it is heptagon (or 7-sided polygon).
A convex octagon has no angles pointing inwards. More precisely, no internal angles can be more than 180°.
When some internal angle is greater than 180°, it is concave.
In option 2 you can see that one angle is pointing inward, then this octagon is concave.
Answer: correct choice is B.
(x+4)(x+4+1) = (x+1)(x+1+11)
(x+4)(x+5) = (x+1)(x+12)
x^2 + 4x+5x+20=x^2+x+12x+12
9x + 20 = 13x + 12
13x-9x = 20-12
4x = 8
x = 2
Answer:
d on edge
Step-by-step explanation:
-3(x+4)(x-2)/x^2-1`
Answer:

Step-by-step explanation:
The formula of a volume of a cone:

r - radius
H - height
We have r = 10cm and H = 16cm. Substitute:

Answer:
Step-by-step explanation: