Respuesta :

we know that

if angle A=45°
then
angle C is also 45°
therefore
if  BC=6 
AB is also 6

applying the Pythagorean theorem
AC²=AB²+BC²--------> AC²=6²+6²------> AC²=72------> AC=6√2

cos 45=6/(6√2)--------> cos 45=1/√2

the answer is the option B
cos 45=1/√2

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Answer:

bc=6

Step-by-step explanation: