What is the length of the missing leg?

Answer:
41
Step-by-step explanation:
This is the formula
a^2 + b^2 = c^2
35^2 + 21^2 = 1666
√1666 = 40.81...
Maybe you can estimate it to 41.
answer:
a = 28 millimeters
step-by-step explanation:
a^2 + 21^2 = 35^2
a^2 + 441 = 1225
a^2 = 784
a = 28 millimeters