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.6.a

Given the endpoints of the diameter of a circle, use the midpoint formula to find its center and then use the Pythagorean Theorem to find its equation.

Example Problems

The equation of a circle is given below.

(x + 4)^{2} + (y - 11)^{2} = 64

What is its center?

The equation of a circle is given below.

(x + 13)^{2} + (y - 1)^{2} = 10

What is its center?

The equation of a circle is given below.

(x + 0.75)^2 + (y + 2.25)^2 = 2.5

What is its center?

Khan Academy Resources

Midpoint formula review 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 Midpoint formula Special right triangles review Hypotenuse, opposite, and adjacent Midpoint formula Solve for a side in right triangles Special right triangles Trigonometric ratios in right triangles Pythagorean theorem challenge Divide line segments 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 Midpoint formula Special right triangles proof (part 2)Special right triangles proof (part 1)30-60-90 triangle example problem Area of a regular hexagon Multi-step word problem with Pythagorean theorem Dividing line segments: graphical Right triangle word problem Dividing line segments Using right triangle ratios to approximate angle measure

1-on-1 AI tutoring aligned to G.6.a. 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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