why the silly mixture of units?
.2 km = 200 metres , so
width ---x
length --- y
xy = 900
2x+2y=200
x+y = 100 ---> y = 100-x
now sub into xy=900
x(100-x) = 900
expand, simplify and use the quadratic equation as in your other question.
let me know what you get
The area of a garden is 900m^2 and has a perimeter of 0.2km. What are the dimensions of the garden?
2 answers
L*W = 900 m^2.
W = 900/L.
2L + 2W = 200 m.
Replace W with 900/L:
2L + 2(900/L) = 200,
L + 900/L = 100,
L^2 + 900 = 100L,
L^2 - 100L + 900 = 0,
L = (-B +- sqrt(B^2-4AC))/2A,
L = (100 +- sqrt(6400))/2 = 90m, and 10 m.
L = 90 m.
W = 900/L = 900/90 = 10 m.
l
62 - 100
l =
W = 900/L.
2L + 2W = 200 m.
Replace W with 900/L:
2L + 2(900/L) = 200,
L + 900/L = 100,
L^2 + 900 = 100L,
L^2 - 100L + 900 = 0,
L = (-B +- sqrt(B^2-4AC))/2A,
L = (100 +- sqrt(6400))/2 = 90m, and 10 m.
L = 90 m.
W = 900/L = 900/90 = 10 m.
l
62 - 100
l =