Is Goblins free for teachers?

Yes. Goblins offers a generous free tier that includes 1 live feedback assignment per week, insights on student mastery and replays, and the ability to upload your own content. The Max plan adds unlimited assignments, superadaptive mode, grade exports, standards growth reports, and SSO/LMS integration, with per-student pricing for schools and districts.

How does Goblins work?

Three simple steps: (1) Share an assignment from thousands of standards-aligned topics using a share code. (2) Students speak and draw their thinking naturally, and Goblins responds with Socratic questioning that sounds just like their teacher. (3) Teachers get real-time formative insights showing what students struggle with and suggestions to inform instruction.

Does Goblins prevent cheating?

Yes. Goblins uses a purpose-trained AI model that evaluates cheating signals in real time. It can detect when students are copying answers, using external tools inappropriately, or not genuinely working through problems. Copy-pasting answers is also blocked.

Can I use my own voice with Goblins?

Yes. Teachers can record their voice and take a selfie to create a custom 3D avatar in about 30 seconds. Students then hear help in their own teacher's voice and see a familiar face, making the experience more personal and effective.

What math levels does Goblins cover?

Goblins covers math from Grade 5 through AP Calculus, including thousands of standards-aligned topics. Teachers can also upload their own content for custom assignments at any level.

Is Goblins FERPA compliant?

Yes. Goblins is FERPA and state compliant. Student data privacy and security are a top priority.

Does Goblins support English Language Learners?

Yes. Goblins supports 30+ languages so teachers don't have to translate every worksheet. It is especially helpful for ELL students who need accessible math instruction in their native language.

AFA.GSR.6.4

Solve problems using the Pythagorean Theorem and trigonometric functions and their inverses in context.

Example Problems

The following are all angle measures (in radians, rounded to the nearest hundredth) whose sine is

0.34

.
Which is the principal value of

\arcsin(0.34)

The following are all angle measures (in radians, rounded to the nearest hundredth) whose cosine is

-0.8

.
Which is the principal value of

\arccos(-0.8)

The following are all angle measures (in radians, rounded to the nearest hundredth) whose sine is

-0.66

.
Which is the principal value of

\arcsin(-0.66)

Khan Academy Resources

Intro to inverse trig functions Solving for a side in right triangles with trigonometry Angles of elevation and depression Trigonometric ratios in right triangles Right triangle trigonometry review Special right triangles review Hypotenuse, opposite, and adjacent Solve for a side in right triangles Special right triangles Trigonometric ratios in right triangles Evaluate inverse trig functions Interpret solutions of trigonometric equations in context Pythagorean theorem in 3D Pythagorean theorem challenge Solve sinusoidal equations (basic)Sinusoidal models word problems Solve sinusoidal equations Solve for an angle in right triangles Right triangle trigonometry word problems Solving for a side in right triangles with trigonometry Trigonometric ratios in right triangles Special right triangles proof (part 2)Special right triangles proof (part 1)30-60-90 triangle example problem Area of a regular hexagon Sine equation algebraic solution set Cosine equation solution set in an interval Pythagorean theorem in 3D Multi-step word problem with Pythagorean theorem Cosine equation algebraic solution set Right triangle word problem Pythagorean theorem with isosceles triangle Using right triangle ratios to approximate angle measure Interpreting solutions of trigonometric equations

1-on-1 AI tutoring aligned to AFA.GSR.6.4. Instant help for students, real-time insights for teachers.

Used in classrooms by 100,000+ students at Baltimore County, Plano ISD, Deer Valley USD, KIPP, and districts nationwide.

Free for teachers, forever →