Watch · explainer animationEntrance-exam arithmetic (solids of revolution)
The volume of a solid made by spinning a right triangle
A right triangle with sides 5, 12 and 13 cm is rotated once around a line. What solid appears, where is its base, and which length is its height? A one-minute animation in which the figure builds up in the order of the judgments.
Domain: Arithmetic
Analysis data (cue → response texts, stage analyses, explanation steps) is shown in the original Japanese. English rendering of the data layer is pending; titles, summaries and observations are in English.
The problem
SubjectRight triangle ABC is rotated once around the line ℓ that contains side AB. What is the volume, in cm³, of the solid this produces? Take π to be 3.14.
CREATE BASE arithmetic materials (solids of revolution, Japanese junior-high entrance level). The original figure is omitted; the animation uses redrawn figures.
Explainer animation
The figure moves to show the flow of judgment in order. Pause or rewind at any time.