Answer:
The effect of doubling the diameter is increased the area to paint as 4 times. So, paint needed is 4 times than it was before. And the area is increased by 9 times when the diameter is increased by a factor of 3. So, paint needed is 9 times than before.
Explanation:
Please remember the concept
If side lengths are in the ratio a : b
Then the area are in the ratio of a^2 :b^2
The volume are in the ratio of a^3 :b^3,
When diameter is doubled, the area ratio becomes
which is simplified to
![x^(2) :4x^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/7ztq14kpuo1zybvbqcri3qkrn1kvstbt95.png)
So, the area is increased by 4 times.
According to this concept , the diameter is increased by the scale factor 3.
Let the diameter of tank is 'x', so the diameter becomes "3x"
So, it's area ratio would be
![x^(2) :(3x)^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/44f49aak037dlyiw5huqkkicmeryjvzbcc.png)
If we simplify it we get
![x^(2) :9x^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/wofsiilzjtijciw7wxlzn2s3fvcs9mp3a1.png)
We conclude that area to be increased by 9 times.