It's 7.4 because the 3 doesn't round the 4 up.
2x+x-7+3x-20=87cm
6x-27=87
6x=114
x=19
Therefore the sides are:12cm, 38cm, and 37cm
Let’s first find the angle y
Angle y = 180-(140+10)(angle sum property)
Angle y = 180-150
Angle y = 30 degrees
Angle x = 180- 110 ( linear pair )
Angle x = 70
Angle z = 180-(70+90)( angle sum property)
Angle z = 180-160
Angle z = 20
It is 12 since 1/6=6^-1=6
implies 2*6=12