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:
x=260 texts
Step-by-step explanation:
85=0.25x+20
Subtract 20 from each side.
65=0.25x
Divide both sides by 0.25.
260=x
260 texts plus the $20 flat fee will cost $85.
Answer: C, I think!
Step-by-step explanation: 3pi equals 9.4247. The square root of 100, is 10. So, that gives us 10/4. That simplified gives us 2.5.
For A, the square root of 36 is 6. 6 is in between 2.5 and pi, so that is not it.
For B, pi to the second power over 3 equals 3.2897, so that’s not it too!
For C, pi over 2 is 1.5708, so that is it, I’m pretty sure!
I’m only in 7th grade, so I’m sorry if it’s wrong!
:)
Sorry if I made typos!
<span>Si el agricultor da 1/4 y 1/8 de su granja, básicamente está regalando 3/8 de su granja si los agrega. Si su granja es una, u 8/8, y resta eso de la cantidad que se necesita, eso es 5/8 de su granja porque 8 / 8-3 / 8 = 5/8. Entonces el granjero todavía posee 5/8 de su granja.</span>
