please help and show work

Step-by-step explanation:
sides opposite to equal angles are equal in length :
angle45 = angle 45
r = s
by Pythagoras theorem :
r² + s² = (9√2 )²
s²+s²= 9 × 9 × 2
2s²= 9× 9×2
s²= 9 × 9
s= √9× 9
s = 9
r= s = 9 units .
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