Question

The diagonal of a rectangular field is 60 metres more than the shorter side. If the longer side is 30 metres more than the shorter side, find the sides of the field.

Answer 1

GỌI CẠNH

ngắn: x, x>0

DÀI: X+ 30

ĐƯỜNG CHÉO
`\sqrt{ x^(2) +(x+30)^(2) }`

`\sqrt{ x^(2) +(x+30)^(2) }` =X+60

`x^(2) +(x+30)^(2)`=
`(x+60)^(2)`

`x^(2) =(x+60)^(2) -(x+30)^(2)`

`x^(2) =(x+60+x+30) * (x+60-x-30)`

`x^(2) = (2x+90)*30`

`x^(2) = 60x+2700`

`\left \{ {{x_(1) =90} \atop {x_(2) _=(-30)}} \right.`

suy ra

x =9 0

nên

ngắn =90m

dài=120m

ĐƯỜNG CHÉO:
`\sqrt{90^(2) +120^(2) }`=150