Answer:
where w is width of rectangle.
Step-by-step explanation:
We are given the following in the question:
The perimeter of a rectangle must be less than 170 feet.
Length of rectangle = 44 feet
Perimeter of rectangle =
Let w be the width of rectangle.
According to the question,
Thus, the width of triangle should be less than 41. Since w cannot take negative values, we can express value of w in interval notation as,
We will solve this using a system of equations. The first part tells us that building a is 190 feet shorter than building b. Our first equation, then, is b=190+a. The second part tells us that the addition of the two buildings' heights is 1480. So our second equation is a + b = 1480. The first equation is already solved for b, so let's sub that value into the second equation for b: a+(190+a)=1480. 2a + 190 = 1480 and 2a = 1290. That means that building a is 645 feet tall. Building b is 190 feet taller, so b = 190 + 645, which is 835.
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:
Diagonal of a rectangular frame = 85 inch
Step-by-step explanation:
Given:
Length of rectangle = 77 inch
Width of rectangle = 36 inch
Find:
Diagonal of a rectangular frame
Computation:
Diagonal of a rectangle = √l² + b²
Diagonal of a rectangular frame = √77² + 36²
Diagonal of a rectangular frame = √5,929 + 1,296
Diagonal of a rectangular frame = √7,225
Diagonal of a rectangular frame = 85 inch
