The line is called the directrix. Here we have a vertical directrix, so a parabola sideways from usual.
Geometry is best done with squared distances. The squared distance from an arbitrary point (x,y) to the vertical line x=2 is

We equate that to the squared distance of (x,y) to the focus (-2,0):



We could call that done. A more standard form might be
Answer:
278.25 cm2
Step-by-step explanation:
If the width of the rectangle is x (cm), as the length is 8cm longer, so that the length of the rectangle is: x + 8 (cm).
In the attached image, we can see the length of each side. Total length of the sides are 90 cm.
=> (x + x + 8) + x + 8 + (x+8) + (x + x + 8) + x + 8 + (x +8) = 90
=> 8x + 48 = 90
=> 8x = 90 - 48 = 42
=> x =42/8 = 5.25 (cm)
=> The width of the rectangle is 5.25cm
=> The length of the rectangle is: 5.25 + 8 = 13.25 cm
=> The area of one rectangle is: Length x Width = 5.25 x 13.25 = 69.5625 cm2
As the 8-sided shape is made from 4 rectangles, so that:
Area of 8 sided shape = 4 x Area of the rectangle = 4 x 69.5625 = 278.25 cm2
Answer:
A=266CM
Step-by-step explanation:
p=2l + 2w l=2x+1 w=x+5
66=2[2x+1] + 2{x+5] l=2x9 + 1 w=9+5
66=4x+2 + 2x+10 l=18+1 w=14
66=6x+12 l=19
66-12=6x
54=6x A=L x W
x=9 A=19 x 14
A=266CM
Let,
the no. of adults be "x"
then, the no. of childern = total people - total adults
= (30 - x)
Now,
According to the quesiton,
2 (30 - x) + 5x = 87
60 - 2x + 5x = 87
60 + 3x = 87
3x = 87 - 60
3x = 27
x = 27 / 3
x = 9
So, there were 9 adults in the group