Answer:
30
Step-by-step explanation:
For a = <xa, ya> and b = <xb, yb>, the dot product is the sum of products ...
a·b = (xa)(xb) + (ya)(yb)
Substituting the given information, you have ...
a·b = 5·4 + 2·5 = 20 + 10
a·b = 30
_____
Some graphing calculators can do such math. There are also dot product calculators available on the Internet. If you have quite a few of these to calculate, you can put the appropriate formula into a spreadsheet.
7. 18.3 divided by 4 is 4.575. 4.575 is closest to 4.5 which would be our answer
8. 14.6 divided by 3 is 4.86. If we round it, then it would be 5 which would be the answer
10. The answer to the problem would be 11.58
X 1 = 3 * cos 120° = - 3 cos 60° = - 3/2 = - 1.5
y 1 = 3 * sin 120° = 3 sin 60° = 3√3 / 2 = 2.598
x 2 = 0.5 * cos 49° = 0.328
y 2 = 0.5 * sin 49° = 0.37735479
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d = [( x 2 - x 1 )² + ( y 2 - y 1 )²]^(1/2)
d = [ ( 0.328 + 1.5 )² + ( 0.37735479 - 2.598) ] ^(1/2)
d = ( 3.341584 +4.931265 )^(1/2)
Answer: The distance is :
d = 2.876256