It is currently 23 Jun 2017, 16:57

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# a parallelogram has 2 sides:14, 18 one of the diagonals is

Author Message
Intern
Joined: 27 Apr 2003
Posts: 35
a parallelogram has 2 sides:14, 18 one of the diagonals is [#permalink]

### Show Tags

08 May 2003, 04:56
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

a parallelogram has 2 sides:14, 18 one of the diagonals is 16, what is the length of the othe diagonal?

jabs
Intern
Joined: 07 May 2003
Posts: 18

### Show Tags

08 May 2003, 13:05

explanation: calculate area of the triangle with sides 16,14,18 using hercules formula ie (area)^2=s(s-a)(s-b)(s-c) where s=(a+b+c)/2
so area=96.

this area=1/2*16*h (h is altitude- diagonals bisect each other, 16 base which is bisected by the altitude)
therefore h=12

other diagonal=2h=24
SVP
Joined: 03 Feb 2003
Posts: 1604

### Show Tags

10 May 2003, 07:06
another feature to remember:

for a parallelogram --- d1^2+d2^2=2*[a^2+b^2]

the sum of squares of diagonals equals to two sums of squares of sides.
Intern
Joined: 07 May 2003
Posts: 1
Location: US

### Show Tags

10 May 2003, 10:13
If you use the above formula diagonal=28
SVP
Joined: 03 Feb 2003
Posts: 1604

### Show Tags

11 May 2003, 22:13
so this should be the answer
Senior Manager
Joined: 02 Mar 2004
Posts: 327
Location: There

### Show Tags

24 Mar 2004, 23:04
Let d1 and d2 be two diagonals.

d1^2 = a^2 + b^2 - 2ab cosA
d2^2 = a^2 +b^2 - 2ab cosB

A+B = 180, cosB = -cosA

d1^2 + d2^2 = 2(a^2+b^2)
16^2 + d2^2 = 2(14^2+18^2)

d2 = 28
24 Mar 2004, 23:04
Display posts from previous: Sort by