Find the area $ A $ of a pyramid if side $a = 8$ and lateral edge $e = 8$.

$A = 174.8513$

STEP 1: find base area $ B $

To find base area $ B $ use formula:

$$ B = a^2 $$

After substituting $ a = 8 $ we have:

$$ B = 8^2 $$ $$ B = 64 $$

STEP 2: find slant height $ s $

To find slant height $ s $ use Pythagorean Theorem:

$$ s^2 + \frac{ a^2 }{ 4 } = e^2 $$

After substituting $ a = 8 $ and $ e = 8 $ we have:

$$ s ^ {\,2} + \frac{ 8^2 }{ 4 } = 8^2 $$ $$ s ^ {\,2} + \frac{ 64 }{ 4 } = 8^2 $$ $$ s ^ {\,2} + 16 = 8^2 $$ $$ s ^ {\,2} = 64 - 16 $$ $$ s ^ {\,2} = 48 $$ $$ s = \sqrt{ 48 } $$$$ s = 4 \sqrt{ 3 } $$

STEP 3: find lateral surface $ L $

To find lateral surface $ L $ use formula:

$$ L = 2 \cdot a \cdot s $$

After substituting $ a = 8 $ and $ s = 4 \sqrt{ 3 } $ we have:

$$ L = 16 \cdot 4 \sqrt{ 3 } $$$$ L = 64 \sqrt{ 3 } $$

STEP 4: find total surface $ A $

To find total surface $ A $ use formula:

$$ A = B + L $$

After substituting $ B = 64 $ and $ L = 64 \sqrt{ 3 } $ we have:

$$ A = 64 + 64 \sqrt{ 3 } $$ $$ A = 64 + 64 \sqrt{ 3 } $$ $$ A = 174.8513 $$

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