SOLUTION: The length of a rectangle is three times its width and the length of its diagonal is 6√10cm.Find the perimeter.

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Question 847873: The length of a rectangle is three times its width and the length of its diagonal is 6√10cm.Find the perimeter.
Found 2 solutions by swincher4391, hamsanash1981@gmail.com:
Answer by swincher4391(1107) About Me  (Show Source):
You can put this solution on YOUR website!
Let the width be x. Then length is 3x.
Notice that when we take two sides with its diagonal we have a right triangle.
Apply pythagorean theorem.
x%5E2+%2B+%283x%29%5E2+=+%286%2Asqrt%2810%29%29%5E2
x%5E2+%2B+9x%5E2+=+360
10x%5E2+=+360
x%5E2+=+36
x=6 <---width
Then our length is 18.

P = 2L + 2W
P = 2(6) + 2(18) = highlight%2848%29 cm

Answer by hamsanash1981@gmail.com(151) About Me  (Show Source):
You can put this solution on YOUR website!
Let width be x then the length will be 3x
by Pythagoras theorem,
x%5E2%2B9X%5E2=+%286sqrt%2810%29%29%5E2
10x%5E2=+360
x%5E2+=+36
x=6
length = 18, Breath = 6
Perimeter = 2(18+6)
= 48 cm