Part a) we know that ABC is a right triangle ∠ACB=45° AC=hypotenuse------> 6√2 cm sin 45=AB/AC-----> AB=AC*sin 45----> AB=6√2*√2/2----> AB=6 cm
the answer part a) is AB=6 cm
Part b) we know that volume of the pyramid=(1/3)*Area of the base*height area of the base=50 cm² height=6 cm so volume of the pyramid=(1/3)*50*6----> 100 cm³