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.
There is 4 1/10's in 2/5.
You do this by turning 2/5 into a fraction with a denominator of 10, so it will be 4/10. 1/10 + 1/10 + 1/10 + 1/10 = 4/10
(cos Ф -cos Ф)² + (cos Ф + cos Ф)²
Firstly: (cos Ф -cos Ф)² = 0² = 0
Secondly :(cos Ф + cos Ф)² = (2cos Ф)². = 4. (cos Ф)² = 4cos² Ф
Mind you when you raise a cosine (or sin or tan...) to the n power, the n power should affect the cosine only and NOT the angle Ф
The answer to your question is x=3
Answer: 18
Step-by-step explanation: The formula for calculating a triangle’s area is 1/2(base•height). This means that 12•3 is 36, which multiplied by 1/2 is 18.
(Hope this helps)
