Answer:
45 cm
Step-by-step explanation:
l = Length of football field is 120 yards
w = Width of football field is 80 yards
The ratio of the sides is 
Now the width of the field is 30 cm = w'

The length of the field in the drawing is 45 cm.
So what is your question cause there isn't one
The cross of YyRr will produce 16 distinct genotypes.
If the two alleles are far enough on the same chromosome, then the Y and R alleles will be distributed independently of one another, so that the genotypic ratio among each allele would be 1:2:1 (YY:Yy:yy, and similarly for the R allele). Then the dihybrid cross will yield a genotypic ratio of 1:2:1:2:4:2:1:2:1 (YYRR:YYRr:YYrr:YyRR:YyRr:Yyrr:yyRR:yyRr:yyrr).
Now, assuming perfect Mendelian inheritance (complete dominance), the phenotypes exhibited by YY and Yy will be considered equivalent, and similarly for RR and Rr, so the phenotypic ratio would be 9:3:3:1 (YR:Yr:yR:yr).