Using proportions, it is found that he needs to achieve 11 consecutive base hits.
The batting average is given by the number of base hits divided by the number of at-bats.
Considering that he gets x hits on his next x at-bats, he will have 12 + x base hits in 98 + x at-bats, and his average will be of:
[tex]Avg = \frac{12 + x}{98 + x}[/tex]
To raise his batting average to .210, [tex]Avg = 0.21[/tex] is needed, hence:
[tex]Avg = \frac{12 + x}{98 + x}[/tex]
[tex]\frac{12 + x}{98 + x} = 0.21[/tex]
[tex]12 + x = 20.58 + 0.21x[/tex]
[tex]0.79x = 8.58[/tex]
[tex]x = \frac{8.58}{0.79}[/tex]
[tex]x = 10.86[/tex]
Rounding up, he needs 11 consecutive base hits.
You can learn more about proportions at https://brainly.com/question/24372153