Solve for a
a=8\sqrt{69}\approx 66.452990903
a=-8\sqrt{69}\approx -66.452990903
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a^{2}+2809=85^{2}
Calculate 53 to the power of 2 and get 2809.
a^{2}+2809=7225
Calculate 85 to the power of 2 and get 7225.
a^{2}=7225-2809
Subtract 2809 from both sides.
a^{2}=4416
Subtract 2809 from 7225 to get 4416.
a=8\sqrt{69} a=-8\sqrt{69}
Take the square root of both sides of the equation.
a^{2}+2809=85^{2}
Calculate 53 to the power of 2 and get 2809.
a^{2}+2809=7225
Calculate 85 to the power of 2 and get 7225.
a^{2}+2809-7225=0
Subtract 7225 from both sides.
a^{2}-4416=0
Subtract 7225 from 2809 to get -4416.
a=\frac{0±\sqrt{0^{2}-4\left(-4416\right)}}{2}
This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -4416 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.
a=\frac{0±\sqrt{-4\left(-4416\right)}}{2}
Square 0.
a=\frac{0±\sqrt{17664}}{2}
Multiply -4 times -4416.
a=\frac{0±16\sqrt{69}}{2}
Take the square root of 17664.
a=8\sqrt{69}
Now solve the equation a=\frac{0±16\sqrt{69}}{2} when ± is plus.
a=-8\sqrt{69}
Now solve the equation a=\frac{0±16\sqrt{69}}{2} when ± is minus.
a=8\sqrt{69} a=-8\sqrt{69}
The equation is now solved.
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