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.

G.28

Verify criteria for showing triangles are similar using a similarity transformation (sequence of rigid motions and dilations) that maps one triangle to another.

G.28.aVerify that two triangles are similar if and only if corresponding pairs of sides are proportional and corresponding pairs of angles are congruent.G.28.bVerify that two triangles are similar if (but not only if) two pairs of corresponding angles are congruent (AA), the corresponding sides are proportional (SSS), or two pairs of corresponding sides are proportional and the pair of included angles is congruent (SAS).

Khan Academy Resources

Triangle similarity review Angle-angle triangle similarity criterion Triangle congruence review Determine congruent triangles Find angles in congruent triangles Solve triangles: angle bisector theorem Determine similar triangles: Angles Special right triangles Determine similar triangles: SSS Solve similar triangles (basic)Solve similar triangles (advanced)Use similar triangles Prove triangle similarity Justify constructions Use ratios in right triangles Prove triangle properties Prove parallelogram properties Prove triangle congruence Determining congruent triangles Geometry proof problem: congruent segments Geometry proof problem: midpoint Finding angles in isosceles triangles (example 2)Finding angles in isosceles triangles Corresponding angles in congruent triangles Triangle similarity postulates/criteria Solving similar triangles Intro to triangle similarity Determining similar triangles Solving similar triangles: same side plays different roles Challenging similarity problem Using similar & congruent triangles 30-60-90 triangle example problem Using the angle bisector theorem Geometry proof problem: squared circle Calculating angle measures to verify congruence Geometry word problem: Earth & Moon radii Geometry word problem: a perfect pool shot Proving triangle congruence Geometry word problem: the golden ratio

1-on-1 AI tutoring aligned to G.28. 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 →