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.C.1.3

Apply the properties of circles and relationships among angles; arcs; and distances in a circle among radii, chords, secants, and tangents to solve problems using algebraic and logical reasoning.

Example Problems

An arc subtends a central angle of

\frac{7}{6}\pi

radians. What fraction of the circumference is the arc?

An arc subtends a central angle of

\frac{7}{4}\pi

radians. What fraction of the circumference is the arc?

An arc subtends a central angle of

\frac{11}{6}\pi

radians. What fraction of the circumference is the arc?

Khan Academy Resources

Challenge problems: Inscribed angles Challenge problems: radius & tangent Arcs, ratios, and radians Challenge problems: Arc length 1 Determining tangent lines: angles Challenge problems: Arc length 2 Challenge problems: Inscribed shapes Determining tangent lines: lengths Challenge problems: Arc length (radians) 2 Challenge problems: Arc length (radians) 1 Inscribed angles Arc length Tangents of circles problems Inscribed shapes Arc measure with equations Arc measure Radians & arc length Arc length from subtended angle: radians Inscribed shapes: find inscribed angle Tangents of circles problem (example 1)Finding arc measures with equations Inscribed shapes: find diameter Solving inscribed quadrilaterals Inscribed angles Inscribed shapes: angle subtended by diameter Tangents of circles problem (example 3)Subtended angle from arc length Intro to arc measure Arc length from subtended angle Arc length as fraction of circumference Finding arc measures Tangents of circles problem (example 2)

1-on-1 AI tutoring aligned to G.C.1.3. 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.

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