Answer:
[tex] 4 \sqrt{5} [/tex]
Step-by-step explanation:
By geometric mean property:
[tex]y = \sqrt{16 \times 4} \\ \\ y = \sqrt{64} \\ \\ y = 8 \\ \\ by \: pythagoras \: theorem: \\ \\ {z}^{2} = {y}^{2} + {4}^{2} \\ \\ {z}^{2} = {8}^{2} + {4}^{2} \\ \\ {z}^{2} = 64 + 16 \\ \\ {z}^{2} = 80 \\ \\ z = \sqrt{80} \\ \\ z = \sqrt{16 \times 5} \\ \\ z = 4 \sqrt{5} [/tex]
