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: two equal triangles constitute rhombus a . if the diagonals of rhombus are 15 cm and 20 cm long . what is the area of each triangle ?
Options: ['a ) 300', 'b ) 150', 'c ) 75', 'd ) 40', 'e ) 20']
c

Problem: 36 people { a 1 , a 2 , . . . , a 36 } meet and shake hands in a circular fashion . in other words , there are totally 36 handshakes involving the pairs , { a 1 , a 2 } , { a 2 , a 3 } , . . . , { a 35 , a 36 } , { a 36 , a 1 } . then size of the smallest set of people such that the rest have shaken hands with at least one person in the set is
Options: ['a ) 11', 'b ) 12', 'c ) 13', 'd ) 15', 'e ) 18']
b

Problem: all the faces of cubes are painted with red colour . it is then cut into 64 equal small cubes . find how many small cubes have only one face coloured ?
Options: a ) 4 , b ) 8 , c ) 16 , d ) 24 , e ) 2
d