SOLUTION: 10/A = A/4.9 ? Ten over A equals A over 4.9 What is A?

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Question 628177: 10/A = A/4.9 ? Ten over A equals A over 4.9
What is A?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+10%2FA+=+A%2F4.9+
Multiply both sides by +4.9A+
+4.9A%2A%2810%2FA%29+=+4.9A%2A%28A%2F4.9%29+
On the left side, the A's cancel
On the right side, the +4.9+'s cancel
+4.9%2A10+=+A%5E2+
+49+=+A%5E2+
Take the square root of both sides
+A+=+7+
and, taking the negative square root of A%5E2
+A+=+-7+
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check the answers:
+10%2FA+=+A%2F4.9+
+A+=+-7+
+10%2F%28-7%29+=+-7%2F4.9+
+-1.4286+=+-1.4286+
OK
+A+=+7+ will check OK too