Réitigh pir^2=13.86

$$\pi r ^ { 2 } = 13.86$$

Réitigh do r.

$$r = \frac{3 \sqrt{\frac{154}{\pi}}}{10} \approx 2.100422582$$

$$r = -\frac{3 \sqrt{\frac{154}{\pi}}}{10} \approx -2.100422582$$

Céimeanna tríd an bhFréamh Chearnach a Fháil

Roinn an dá thaobh faoi \pi .

$$\frac{\pi r^{2}}{\pi }=\frac{13.86}{\pi }$$

Má roinntear é faoi \pi cuirtear an iolrúchán faoi \pi ar ceal.

$$r^{2}=\frac{13.86}{\pi }$$

Roinn 13.86 faoi \pi .

$$r^{2}=\frac{693}{50\pi }$$

Tóg fréamh chearnach an dá thaobh den chothromóid.

$$r=\frac{231}{5\sqrt{154\pi }} r=-\frac{231}{5\sqrt{154\pi }}$$

Céimeanna ag Baint Úsáid as an bhFoirmle Chearnach

Bain 13.86 ón dá thaobh.

$$\pi r^{2}-13.86=0$$

Tá an chothromóid seo i bhfoirm chaighdeánach: ax^{2}+bx+c=0. Cuir \pi in ionad a, 0 in ionad b, agus -13.86 in ionad c san fhoirmle chearnach, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$r=\frac{0±\sqrt{0^{2}-4\pi \left(-13.86\right)}}{2\pi }$$

Cearnóg 0.

$$r=\frac{0±\sqrt{-4\pi \left(-13.86\right)}}{2\pi }$$

Méadaigh -4 faoi \pi .

$$r=\frac{0±\sqrt{\left(-4\pi \right)\left(-13.86\right)}}{2\pi }$$

Méadaigh -4\pi faoi -13.86.

$$r=\frac{0±\sqrt{\frac{1386\pi }{25}}}{2\pi }$$

Tóg fréamh chearnach \frac{1386\pi }{25}.

$$r=\frac{0±\frac{3\sqrt{154\pi }}{5}}{2\pi }$$

Réitigh an chothromóid r=\frac{0±\frac{3\sqrt{154\pi }}{5}}{2\pi } nuair is ionann ± agus plus.

$$r=\frac{231}{5\sqrt{154\pi }}$$

Réitigh an chothromóid r=\frac{0±\frac{3\sqrt{154\pi }}{5}}{2\pi } nuair is ionann ± agus míneas.

$$r=-\frac{231}{5\sqrt{154\pi }}$$

Tá an chothromóid réitithe anois.

$$r=\frac{231}{5\sqrt{154\pi }} r=-\frac{231}{5\sqrt{154\pi }}$$