Evaluate square root of 21* square root of 15

$\sqrt{21} \cdot \sqrt{15}$

Step 1

Combine using the product rule for radicals.

$\sqrt{21 \cdot 15}$

Step 2

Multiply $21$ by $15$ .

$\sqrt{315}$

Step 3

Rewrite $315$ as $3^{2} \cdot 35$ .

Factor $9$ out of $315$ .

$\sqrt{9 (35)}$

Rewrite $9$ as $3^{2}$ .

$\sqrt{3^{2} \cdot 35}$

$\sqrt{3^{2} \cdot 35}$

Step 4

Pull terms out from under the radical.

$3 \sqrt{35}$

Step 5

The result can be shown in multiple forms.

Exact Form:

$3 \sqrt{35}$

Decimal Form:

$17.74823934 \dots$

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