Answer:
<h3>There are 100 girls in the school</h3>
Step-by-step explanation:
Let the total number of people be x
To find the number of girls in the class we must first find the total number of people in the class
First find the total parts
That's
2 + 5 = 7
2/7 of the total number of people are boys
So we have
2/7 × x = 40
Multiply through by 7
2x = 280
Divide both sides by 2
x = 140
There are 140 people in the school
Finding the number of girls we have
5/7 × 140
= 100
There are 100 girls in the school
Hope this helps you
First of all, triangles angles add up to 180 degrees.
BCD=120. To find BCA subtract 180-120 to get 60 degrees.
We know what ABC is, it equals 85, so far we have 2 angles.
Lets add them up, 85+60=145
Since the angles must add up to equal 180 we're going to subtract 180-145
Which equals 35, BAC=35 degrees.
-Seth
Answer:
AnB = { 2,4}
Step-by-step explanation:
A={1,2,3,4,5} and B={2,4}
AnB means A intersect B or what is common to both A and B
AnB = { 2,4}
Answer: 96
Step-by-step explanation: take 12 (1 dozen) and times it by 8
12x8=96
Answer:
The depth of the reflector is 700 feet.
Step-by-step explanation:
The cross section of a parabolic reflector is just a parabola (see the figure below). Because it has a vertical axis of symmetry and its vertex is at (0,0) the equation of the parabola is:
![y=4px^{2}\,\,(1)](https://tex.z-dn.net/?f=y%3D4px%5E%7B2%7D%5C%2C%5C%2C%281%29%20)
With p the distance to the focus (p=6ft), the equation for our particular case is:
![y=4(6)x^{2}\,\,(2)](https://tex.z-dn.net/?f=y%3D4%286%29x%5E%7B2%7D%5C%2C%5C%2C%282%29)
![y=24x^{2}\,\,(3)](https://tex.z-dn.net/?f=y%3D24x%5E%7B2%7D%5C%2C%5C%2C%283%29)
Note that because the reflector extends 5.5 feet to either side of the vertex, the extreme sides of the parabola are on the curve so they satisfy our parabola equation (3). Let’s concentrate on the right extreme of our parabola with x-position 5.5 ft using this number on (3) equation we can find the respective y-position
![y=24(5.5)^{2}\,\,\simeq\mathbf{700\,ft}(4)](https://tex.z-dn.net/?f=y%3D24%285.5%29%5E%7B2%7D%5C%2C%5C%2C%5Csimeq%5Cmathbf%7B700%5C%2Cft%7D%284%29)
and that correspond to the depth of the parabolic reflector.