Surprising Times You Can Use Desmos
- 4 hours ago
- 4 min read
By Laura Whitmore
Most students fall into one of two camps on SAT Math: they either overuse Desmos or barely touch it at all. Both approaches can cost you time and points.
The truth is, some SAT math problems are slower to solve with Desmos. But others become dramatically easier when you use it the right way. The key is learning to recognize the difference quickly.
I’m Laura Whitmore, and I’ve been coaching the SAT for nearly 20 years. I founded Strategic Test Prep in 2021 to help students raise their scores using clear, practical strategies, and I scored a 1590 on the Digital SAT. This lesson is based on the exact kinds of math questions students can expect to encounter on the updated 2026 exam.
In this post, we’ll walk through three SAT-style math problems that don’t obviously look like “Desmos problems,” but are much more efficient when solved using the calculator. These examples will help you build the judgment high scorers use to decide when Desmos is the smartest move.
👉 Don't feel like reading? Watch the full video here.
💡 Problem 1: Percent Relationships Made Simple With Lists
At first glance, this type of problem looks like it needs to be solved algebraically. You’re given multiple statements relating A, B, and C using percentages, and then asked to find what percent one value is of another.
Many students would immediately start writing equations and substituting. That works—but it’s slow and easy to mess up.
A faster approach is to use Desmos’s list feature.
Each statement in the problem can be written as an equation:
A is 540% of B
A is 90% of C
C is P% of B
Instead of solving step by step, you can enter all of these relationships into Desmos at once using lists. By placing the variables on one side and the expressions on the other, Desmos solves the system instantly and shows the value of each variable—including P.
In this case, Desmos quickly reveals the value of P without any messy algebra. What looks like a complicated percent problem becomes a quick setup-and-go solution.
This is a great example of a problem that doesn’t scream “use Desmos,” but becomes much faster when you do.
💡Problem 2: Finding a Circle Equation Using Regression
This next problem looks even more intimidating at first. You’re given the center of a circle and the radius, and asked to determine a missing value in the equation.
Most students would try to plug into the standard circle formula and solve algebraically. But there’s a more efficient path: regression.
To run a regression for a circle, you need at least three points on the circle. The problem already gives you everything needed to find them.
If the center is at (6, 8) and the radius is 13, you can generate points by moving:
13 units up
13 units to the side
13 units down
That gives you three points on the circle. Once those points are entered into a Desmos table, you can input the equation format given in the problem and use regression (by replacing equals signs with a tilde).
Desmos will then calculate the parameters in the equation for you. Instead of solving manually, you simply read off the value you’re looking for.
What looked like a long algebra problem becomes a quick setup using points and regression.
💡Problem 3: Visualizing Triangle Relationships With Sliders
The third problem is a perfect example of when graphing can give you instant clarity.
You’re given triangles with vertices defined in terms of a constant and asked about angle relationships. Many students try to sketch the diagram by hand or solve symbolically.
But this setup is ideal for Desmos.
When coordinates depend on a constant, you can create a slider and graph the points directly. Once plotted, Desmos makes the geometry much easier to see. As you move the slider, the triangles change size but keep the same shape.
This makes an important relationship obvious: the triangles remain similar, and certain angles stay complementary.
From the visual alone, you can see that the two non-right angles in a right triangle must add up to 90 degrees. So if one angle is T, the other must be 90 − T.
Instead of working through a long chain of logic, the diagram makes the relationship clear in seconds.
⏰ The Big Takeaway
High scorers don’t constantly ask, “Should I use Desmos?” They ask, “Is Desmos the smartest choice here?”
Sometimes the answer is no. But in the three examples above, using Desmos turns complicated-looking problems into quick, efficient setups.
The goal isn’t to rely on Desmos for everything. It’s to recognize the moments when it saves time, reduces errors, and helps you see relationships more clearly.
When you build that judgment, you start moving through SAT Math faster—and with a lot more confidence.
⚡️Want More Help Mastering Desmos?
If you want to get better at recognizing which SAT Math problems should be solved with Desmos—and which ones shouldn’t—we go much deeper into this in our live Desmos Crash Course.
In this focused 2-hour session, we teach students how to:
Spot Desmos-friendly problems instantly
Use sliders, lists, tables, and regressions strategically
Avoid common calculator mistakes that cost time and points
Build faster decision-making skills for test day
If you're taking the March SAT, this class can make a real difference in both speed and confidence. Check out details for our upcoming Desmos Crash Course and save your spot while seats are still available.
Happy Prepping,
