Please answer this!!

Answer:
BC = 6.8
Step-by-step explanation:
Since this is a right triangle, we can use trig functions
tan theta =opp /adj
tan C = AB / BC
tan 45 = 6.8/ BC
BC = 6.8 / tan 45
BC = 6.8 / 1
BC = 6.8
Answer: Choice D. 6.8
Step-by-step explanation:
45,45,90 triangles, memorize that the short sides are equal to each other in length and are [tex]\frac{1}{\sqrt{2} }[/tex] the length of the long side.