In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: the perimeter of an isosceles right triangle is 10 + 10 sq rt 2 . what is the length of the hypotenuse of the triangle ? 
Options: a ) 5 , b ) 6 , c ) 7.07 , d ) 8 , e ) 9
c

Problem: in an electric circuit , two resistors with resistances 3 ohm and 5 ohm are connected in parallel . in this case , if r is the combined resistance of these two resistors , then the reciprocal of r is equal to the sum of the reciprocals of two resistors . what is the value ? 
Options: ['a ) 15 ohms', 'b ) 15 / 8 ohms', 'c ) 1 / 8 ohms', 'd ) 8 / 15 ohms', 'e ) 8 ohms']
b

Problem: how many 4 x 5 x 8 cubes could fit in a 10 x 16 x 84 box ? 
Options: a ) 84 , b ) 90 , c ) 85 , d ) 77 , e ) 64

a