Hello,
In my old memories,
p(μ-2σ<=X<=μ+2σ)=95%
p(μ-3σ<=X<=μ+3σ)=99%
1000-2*200=1000-400=600
1000+2*200=1000+400=1400
Answer A
3⁹ is the same as doing:
3 * 3 * 3 * 3 * 3 * 3 * 3 * 3 * 3
What I would do it is narrow it down piece by piece.
3 * 3 * 3 = 27. Do that 3 times, now you are left with:
27 * 27 * 27
27 * 27 or 27² = 729.
That leaves you with:
729 * 27
You can multiply by hand or use a calculator to get your answer of 19683.
To check your answer, plug 3⁹ into a calculator. Your answer should match this.
I believe the answer is True
Interior angles of a square always sum to 360°. A reflection in the x-axis would not change this.