Question 946478
Let W=Width; Let L=Length=3W; Let P=Perimeter=2(L+W)=20m; Area=L*W
Substitute for L in perimeter equation to get an equation you can solve for W:
P=2(L+W)
20m=2(3W+W)
20m=2(4W)
20m=8W
2.5m=W ANSWER 1 Width (breadth)=2.5m
Here we can find the area using width, or continue to find length (see after --OR-- below)
AREA: METHOD 1:
Area=L*W Substitute for L
Area=3W*W
{{{Area=3W^2}}} Plug in value for W from above
{{{Area=3(2.5m)^2}}}
{{{Area=3(6.25sqm)}}}
Area=18.75 sq m ANSWER 2: Area is 18.75 square meters
  
  --OR--

AREA: METHOD 2:
Substitute W value in perimeter equation to find length(L):
P=2(L+W)
20m=2(L+2.5m)
20m=2L+5.0m Subtract 3m from each side
15m=2L Divide each side by 2
7.5m=L
Find Area:
Area=L*W=7.5m*2.5m=18.75 sq m.ANSWER 2: Area is 18.75 square meters