Answer:
We use cosine rule also called cosine law which states
c^2=a^2+b^2-2abcosC
given
a=8cm, b=7cm, c=9cm cos C?
9^2=8^+7^2-2*8*7 cos C
expand
81=64+49-112 cos C
like terms together
81-113=-112 cos C
-32=-112cos C
multiply both sides by -1
32=112cos C
divide both sides by 112
32/112=cos C
cosC=0.2857
find cos inverse of 0.2857
angle C= 73.40
Answer:
2 gallons of pure alcohol
Step-by-step explanation:
Let x represent the number of gallons of pure alcohol needed, and create an equation:
4(0.25) + x(1) = (x + 4)0.5
1 + x = 0.5x + 2
x = 0.5x + 1
0.5x = 1
x = 2
So, 2 gallons of pure alcohol should be added.
Answer:
An imaginary line would need to be drawn at any angle to the center of the side opposite the angle to reflect across an axis of symmetry so that a regular pentagon can carry onto itself. Hope this answer helps.
Answer:
59.09%
Step-by-step explanation:
35-22=13
13/2= .59090909=59.09%
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