To find side $ b $ use Pythagorean Theorem:

$$ a^2 + b^2 = d^2 $$

After substituting $a = 92\, \text{cm}$ and $d = 100\, \text{cm}$ we have:

$$ \left( 92\, \text{cm} \right)^{2} + b^2 = \left( 100\, \text{cm} \right)^{2} $$ $$ b^2 = \left( 100\, \text{cm} \right)^{2} - \left( 92\, \text{cm} \right)^{2} $$ $$ b^2 = 10000\, \text{cm}^2 - 8464\, \text{cm}^2 $$ $$ b^2 = 1536\, \text{cm}^2 $$ $$ b = \sqrt{ 1536\, \text{cm}^2 } $$$$ b = 16 \sqrt{ 6 }\, \text{cm} $$

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