Question

The sides (in cm) of an equilateral triangle are 2x-3y+1 , x+y-1, 3x-y-9 . Find thePERIMETER.

Answer 1

In eq. triangle all sides are equal
so, 2x-3y+1=3x-y-9
-2y+10=x ---(1)
and
2x-3y+1=x+y-1
x=4y-2 ---(2)
Comparing (1) & (2)
-2y+10=4y-2
6y=12
y=2
and x=6
so, sides=x+y-1
=7
Perimeter=3×7=21cm

Answer 2

Answer:

21 cm

Step-by-step explanation:

We are given that The sides (in cm) of an equilateral triangle are 2x-3y+1 , x+y-1, 3x-y-9

All sides of equilateral triangle are equal.

So, $2x-3y+1=x+y-1=3x-y-9$

So, $2x-3y+1=x+y-1$

$x-4y=-2$ ---A

$x+y-1=3x-y-9$

$2x-2y=8$

$x-y=4$  --B

Substitute the value of x in A

$4+y-4y=-2$

$4-3y=-2$

$3y=6$

y=2

Substitute the value of y in B

$x-2=4$  

x=6

So, side of equilateral triangle = x+y-1 = 6+2-1 = 7 cm

Perimeter of equilateral triangle = $3 \times side = 3 \times 7 = 21 cm$

Hence the perimeter of equilateral triangle is 21 cm