As soon as I read this, the words "law of cosines" popped
into my head. I don't have a good intuitive feeling for the
law of cosines, but I went and looked it up (you probably
could have done that), and I found that it's exactly what
you need for this problem.
The "law of cosines" relates the lengths of the sides of any
triangle to the cosine of one of its angles ... just what we need,
since we know all the sides, and we want to find one of the angles.
To find angle-B, the law of cosines says
b² = a² + c² - 2 a c cosine(B)
B = angle-B
b = the side opposite angle-B = 1.4
a, c = the other 2 sides = 1 and 1.9
(1.4)² = (1)² + (1.9)² - (2 x 1 x 1.9) cos(B)
1.96 = (1) + (3.61) - (3.8) cos(B)
Add 3.8 cos(B) from each side:
1.96 + 3.8 cos(B) = 4.61
Subtract 1.96 from each side:
3.8 cos(B) = 2.65
Divide each side by 3.8 :
cos(B) = 0.69737 (rounded)
Whipping out the
trusty calculator:
B = the angle whose cosine is 0.69737
= 45.784° .
Now, for the first time, I'll take a deep breath, then hold it
while I look back at the question and see whether this is
anywhere near one of the choices ...
By gosh ! Choice 'B' is 45.8° ! yay !
I'll bet that's it !
Answer:
Step-by-step explanation:
At Greg's Gas Station premium gasoline costs $0.14 more per gallon than regular gasoline .
Let the cost of regular gasoline be $x per gallon, then the cost of premium gasoline per gallon will be x + 0.14
If Mr. Adams spent $36.25 on 12.5 gallons of regular gasoline, it means that 12.5x = 36.25
x = 36.25/12.5 = $2.9
The cost of regular gasoline is $2.9 per gallon
Therefore, cost of premium gasoline per gallon will be 2.9+ 0.14 = 3.04
if he bought 12.5 gallons of premium gasoline instead, he would have paid
12.5× 3.04 = $38
The amount that he would have spent more will be
38 - 36.25 = $1.75
Answer:
your answer is D.
Step-by-step explanation:
took quiz
The cable should be 50 feet.
If you draw the picture, you will see that you have a right triangle.
Let's just use the Pythagorean Theorem to find the hypotenuse (or cable).
30^2 + 40^2 = c^2
2500 = c^2
50 = c
Desmos.com and plug in the equation
