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 May 20th, 2019, 08:00 PM #1 Senior Member   Joined: Mar 2019 From: TTF area Posts: 180 Thanks: 1 Algebra word problem The formula for the length of the hypotenuse of a right-angled triangle, whose short sides are p, q is r² = p² + q² 1. Make p the subject of this formula. 2. Evaluate the shortest side of a right-angled triangle, if the other two sides have lengths given by q = 9.3 and r = 11.4. State the answer accurate to 1 d.p. Last edited by skipjack; May 21st, 2019 at 08:26 AM.
 May 20th, 2019, 08:47 PM #2 Senior Member     Joined: Oct 2018 From: USA Posts: 102 Thanks: 77 Math Focus: Algebraic Geometry $\displaystyle r^{2} = p^{2}+q^{2}$ $\displaystyle r^{2} - q^{2} = p^{2}$ $\displaystyle \sqrt{r^{2} - q^{2}} = p$ You should be able to go from here, if not, let me know. Thanks from topsquark Last edited by Greens; May 20th, 2019 at 08:47 PM. Reason: Latex
 May 20th, 2019, 09:38 PM #3 Senior Member   Joined: Mar 2019 From: TTF area Posts: 180 Thanks: 1 So does p = √(r+q)(r-q), -√(r+q)(r-q)? Last edited by skipjack; May 21st, 2019 at 08:32 AM.
May 20th, 2019, 11:39 PM   #4
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Quote:
 Originally Posted by helpmeddddd -√(r+q)(r-q)?
Since we're dealing with triangle lengths, we can't have negative length.

 May 21st, 2019, 08:35 AM #5 Global Moderator   Joined: Dec 2006 Posts: 21,124 Thanks: 2332 p = √(r² - q²) suffices. If q = 9.3 and r = 11.4, what value does that give you for p (to 1 d.p.)?
May 21st, 2019, 12:42 PM   #6
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is there a good formula to use for this?
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Last edited by helpmeddddd; May 21st, 2019 at 12:53 PM.

 May 21st, 2019, 02:47 PM #7 Senior Member     Joined: Oct 2018 From: USA Posts: 102 Thanks: 77 Math Focus: Algebraic Geometry https://en.m.wikipedia.org/wiki/Pythagorean_theorem So in your case: $p^{2}+q^{2} = r^{2}$ Thanks from topsquark
May 21st, 2019, 04:23 PM   #8
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Quote:
 Originally Posted by helpmeddddd State the answer accurate to 1 d.p.
That requirement is unclear. It doesn't tell you to round your answer or to truncate your answer. What exactly does "accurate to 1 d.p." mean?

May 21st, 2019, 04:29 PM   #9
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Quote:
 Originally Posted by helpmeddddd The formula for the length of the hypotenuse of a right-angled triangle, whose short sides are p, q is r² = p² + q² 1. Make p the subject of this formula. 2. Evaluate the shortest side of a right-angled triangle, if the other two sides have lengths given by q = 9.3 and r = 11.4.
Are you a student attending math classes?

If so, seems to be something wrong with your teacher...

May 21st, 2019, 08:43 PM   #10
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Quote:
 Originally Posted by Greens https://en.m.wikipedia.org/wiki/Pythagorean_theorem So in your case: $p^{2}+q^{2} = r^{2}$
why am I finding the length of r as I already know it?

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