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Posted by **lisa** on Thursday, July 14, 2011 at 8:08pm.

- geometry - incomplete -
**Ms. Sue**, Thursday, July 14, 2011 at 8:18pmWhat is the perimeter?

- geometry -
**lisa**, Thursday, July 14, 2011 at 8:23pman 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 -
**Ms. Sue**, Thursday, July 14, 2011 at 8:31pmHow do you think you should solve this problem?

- geometry -
**lisa**, Thursday, July 14, 2011 at 8:36pmI really have no idea. I am more confused with every question.

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 8:45pmAre you sure that the perimeter is 60 inches?

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

Solve for x.

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 8:49pmIf the perimeter is 90 inches, forget the solution I posted above.

- geometry -
**lisa**, Thursday, July 14, 2011 at 8:58pm19.2 cm?

- geometry -
**lisa**, Thursday, July 14, 2011 at 9:00pmx = 19.2cm? (the perimeterr is 60 in.)

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 9:10pmSubstitute 19.2 for x and see if it works.

- geometry -
**lisa**, Thursday, July 14, 2011 at 10:11pmIt does...right? Oh Lord...

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 10:17pmI'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 -
**lisa**, Thursday, July 14, 2011 at 10:20pmhow about x=6...that works.

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 10:29pmYay! You got it!

- geometry -
**lisa**, Thursday, July 14, 2011 at 10:36pmreally..cuz that answer I didnt convert cm to inches. when I do I get x = 18.86 now. Please confirm. my brain hurts.

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 10:48pmAre 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 -
**lisa**, Thursday, July 14, 2011 at 10:57pmno, 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

Whadda ya think?

- geometry -
**Ms. Sue**, Thursday, July 14, 2011 at 10:58pmAhh! It looks like you're right.