Answer:
-3
Step-by-step explanation:
The ratio of the tetras and the platies is 3:1
Mean is all of the numbers added up and then divided by the number of the numbers. so for example; 32+36+38+39+42+43+44+47+49+50 divided by 10 do that and then group 2, and if you already know how to do that then answer the questions
A^2+b^2= 15^2
b=a-3
Use substitution
a^2+(a-3)^2= 225
a^2+a^2-6a+9=225
2a^2-6a=-216
2a^2-6a+216=0
2(a^2-3a+108)
2(a-12)(a+9)
(a-12)=0
a=12
(a+9)=0
a=-9
A is -9 or 12, but since an object can't have a negative length or width, a must be 12.
Plug this value of a in.
b=(12)-3
b=9
Final answer: Length=9, width=12