Answer:
15degrees
Step-by-step explanation:
From the given diagram
<1+<2 + <DCB = 180
<1+<2+120 = 180
<1+<2 = 180 - 120
<1+<2 = 60
<2 = 60 - <1
<2 = 60 - 45
<2 = 15degrees
Hence the measure <2 is 15degree
<span>square root of 81 = 9 so it is rational number
5 divided by 3.14 = 5/3.14 = 500/314 so it is rational as well.
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One way of doing it is by using the properties of summing things, like factoring out the minus sign:
<span><span>∑<span>n=2</span>8</span><span>−(n−5)</span>=−<span>∑<span>n=2</span>8</span><span>(n−5)
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and splitting it up into two parts and again factor
<span>=−<span>(<span><span>∑<span>n=2</span>8</span><span>n−5<span>∑<span>n=2</span>8</span>1</span></span>)
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The last sum is just counting how many numbers there are from 2 to 8, which is 7 (you can do it on your fingers). The first one can be calculated fast if we are clever and use this identity:
<span><span>∑<span>n=1</span>m</span>n=<span><span>m(m+1)</span>2
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So what we get is
<span><span>=−<span>(<span>−1+<span><span>8(8+1)</span>2</span>−7</span>)</span>=8−72/2=8−36=−28.</span></span>
Answer:
Dominos is the better deal.
