I'm assuming the dimensions are like the measures of whatever the figure is. Volume, length,width,height,circumference,radius,diameter,area,perimeter,etc. whatever you are working with, that will help you find the dimensions of the figure:)
12 girls out of 19, how many out of 76
12 - x
19 - 76
Cross product:
19x= 1152
/19. /19
x= ~61
There are (around) 61 girls