Once you know the proportion from the sample, assume it is the same for all 1,050 students. How can you use that proportion to find an expected count out of 1,050?

Let $x$ be the expected number of students in the whole school who plan to attend a four-year college and set up an equation like $x/1050 = 135/200$. Then solve for $x$ and compare your result to the answer choices.

In a new expression line, type 1050 * 135 / 200 and look at the numerical result that Desmos displays. Then choose the answer option that is closest to this value.

We are told that 135 out of 200 surveyed students plan to attend a four-year college.

Compute the proportion:

So, about $67.5\%$ of the surveyed students plan to attend a four-year college.

Assume the same proportion applies to all 1,050 students at the school.

Let $x$ be the expected number of students (out of 1,050) who plan to attend a four-year college. Set up a proportion:

Solve for $x$ by multiplying both sides by 1,050:

This expression gives the expected number of students.

Now compute the value of $x$:

First, $1050 \cdot 0.6 = 630$ and $1050 \cdot 0.075 = 78.75$, so

We expect about 709 students; among the answer choices, 710 is the closest, so the correct answer is 710.