# geometry

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an isosceles triangle has a perimeter of in. the congruent sides measure (2x+9)cm. The length of the third side is 3 x cm. what is the value of x?

• geometry - incomplete -

What is the perimeter?

• geometry -

an isosceles triangle has a perimeter of 60 in. the congruent sides measure (2x+9)cm. The length of the third side is 3x cm. what is the value of x?

Again...sorry. = )

• geometry -

How do you think you should solve this problem?

• geometry -

I really have no idea. I am more confused with every question.

• geometry -

Are you sure that the perimeter is 60 inches?

2(2x + 9) + 3x = 60

Solve for x.

• geometry -

If the perimeter is 90 inches, forget the solution I posted above.

• geometry -

19.2 cm?

• geometry -

x = 19.2cm? (the perimeterr is 60 in.)

• geometry -

Substitute 19.2 for x and see if it works.

• geometry -

It does...right? Oh Lord...

• geometry -

I'll bet the perimeter is 60 cm.

2(2x + 9) + 3x = 60
2(38.4 + 9) + 3(19.2) = 60
94.8 + 57.6 does not equal 60

Work this equation.

2(2x + 9) + 3x = 60

You should find that x is a whole number between 5 and 10.

• geometry -

• geometry -

Yay! You got it!

• geometry -

really..cuz that answer I didn't convert cm to inches. when I do I get x = 18.86 now. Please confirm. my brain hurts.

• geometry -

Are you absolutely sure that the perimeter was given in inches, not centimeters?

If you are -- then I'm off base because I've figured the perimeter as 60 centimeters.

• geometry -

no, the perimeter is 60 inches. ha..hence the confusion.
1 in = 2.54 cm
60 in =152.4cm
7x=152.4-18
7x=134.4 / 7
x=19.2cm

• geometry -

Ahh! It looks like you're right.