
Add 7 to both sides

At the left hand side 7 will cancel 7
At the right hand side 7 will add up

Divide through by 2

simplify the fraction

Special Triangles Theorem
leg1=leg2=a
hypotenuse=a√2=10
Both Legs are 5√2 inches
Because, 9 x 9 = 81. Hope I helped!
The answer to this question is 0.004