Laatst bijgewerkt: 19 augustus 2026
Rechte Cirkelkegel Calculator
Makers
Dharmendra SinghBeoordelaars
Makers
Dharmendra SinghBeoordelaars
Quick Answer
A right circular cone uses the linked formulas l = √(r² + h²), V = (1/3)πr²h, and surface area = πr(r + l). This calculator starts from radius and height, then returns slant height, volume, lateral area, total surface area, and base area for a complete geometric summary.
For a right circular cone, first find slant height with the Pythagorean theorem, then use one-third pi r squared h for volume.
Belangrijkste Punten
- A right circular cone contains a right triangle with radius, height, and slant height.
- Slant height is found with l = √(r² + h²).
- Volume is V = (1/3)πr²h.
- Lateral area is πrl.
- Total surface area equals lateral area plus base area.
Makers
Dharmendra SinghBeoordelaars
Makers
Dharmendra SinghBeoordelaars
Formule
l = √(r² + h²), V = (1/3)πr²h, surface area = πr(r + l)
Waarbij:
- r=Radius(units)
- h=Height(units)
- l=Slant height(units)
- V=Volume(cubic units)
Opgeloste voorbeelden
Radius 3 and height 4
A 3-4-5 right triangle appears inside the cone.
- 1Find slant height: √(3² + 4²) = 5.
- 2Compute volume: (1/3)π × 3² × 4 = 12π ≈ 37.699111.
- 3Compute total surface area: π × 3 × (3 + 5) = 24π ≈ 75.398224.
Radius 5 and height 12
Another neat Pythagorean cone example.
- 1Find slant height: √(5² + 12²) = 13.
- 2Compute volume: (1/3)π × 25 × 12 = 100π ≈ 314.159265.
- 3Compute lateral area: π × 5 × 13 = 65π ≈ 204.203522.
Radius 7 and height 24
Large dimensions still follow the same formulas.
- 1Find slant height: √(7² + 24²) = 25.
- 2Compute volume: (1/3)π × 49 × 24 = 392π ≈ 1231.504321.
- 3Compute total surface area: π × 7 × (7 + 25) = 224π ≈ 703.716755.
Introductie
The Right Circular Cone Calculator combines the key formulas for a right circular cone into one place so you can move from base measurements to full geometric properties without rebuilding the diagram each time. Starting with radius and height, it computes slant height, volume, lateral area, total surface area, and base area. Because a right cone contains a right triangle formed by the radius, height, and slant height, the calculations also provide a clear link between solid geometry and the Pythagorean theorem.
What defines a right circular cone
A right circular cone has a circular base and an apex directly above the center of that base. The segment from the apex to the base center is perpendicular to the base, which is why the word right appears in the name.
The base is a circle.
The apex sits above the base center.
Radius and height form a right triangle with the slant height.
Volume and area formulas depend on those measurements.
Main formulas explained
Three formulas drive the calculator: slant height from the Pythagorean theorem, volume from one-third of the matching cylinder volume, and surface area from combining the lateral area with the base area.
l = √(r² + h²).
V = (1/3)πr²h.
Lateral area = πrl.
Total surface area = πr(r + l).
Worked example
For radius 3 and height 4, the slant height is 5 because 3² + 4² = 5². The volume is 12π and the total surface area is 24π, so this is a good benchmark example for checking hand calculations.
Solve the triangle first.
Then compute the volume.
Next compute lateral area.
Add the base area for total surface area.
Inputs and outputs
You only need radius and vertical height as inputs. The calculator then returns the volume as the primary result along with slant height, lateral area, total surface area, and base area for context.
Radius and height must both be positive.
Volume is the main answer for many applications.
Slant height supports area calculations.
Base area helps compare the cone with cylinders and circles.
Common mistakes
Users often confuse slant height with vertical height or forget that total surface area includes the base. Another common mistake is multiplying by π too early and rounding before later steps are finished.
Do not swap height and slant height.
Do not forget the one-third factor in volume.
Do not omit the base when total surface area is requested.
Do not round intermediate values too early.
Where people use these formulas
Right circular cone formulas appear in manufacturing, packaging, funnels, tanks, traffic cones, and classroom geometry. Even when software handles the final model, a fast formula check helps confirm dimensions and material estimates.
Container and funnel design.
Material estimation for conical surfaces.
Classroom geometry and exam review.
Spreadsheet verification for engineering calculations.
Manual method versus calculator use
The formulas are standard, but a calculator saves time when you need several outputs at once or when the numbers are decimals. A good habit is to identify the inside right triangle first and estimate the order of magnitude before reading the exact answer.
Use a hand sketch to label r, h, and l.
Estimate slant height before calculating.
Check whether the volume should be much smaller than a cylinder with the same base and height.
Use the calculator when you need all the derived measures together.
Snelreferentiekaart
Right circular cone quick reference
Snelreferentie • Rechte Cirkelkegel Calculator
l = √(r² + h²), V = (1/3)πr²hGeldig bereik: Use positive radius and height values.
Veelvoorkomende Waarden
⚠ Let op
- •Do not confuse slant height with vertical height.
- •Do not forget the one-third factor in the volume formula.
- •Do not omit the base when finding total surface area.
- •Do not round before derived outputs are finished.
Pro Tips
- →Solve the slant height first.
- →Compare cone volume with the matching cylinder volume for a quick check.
- →Keep π symbolic during hand work as long as possible.
- →Use the total surface area formula only after l is known.
FAQ
What is a right circular cone?
It is a cone whose apex is directly above the center of its circular base, making the height perpendicular to the base.
How do you find the slant height?
Use the Pythagorean theorem: l = √(r² + h²).
Why is the cone volume one-third of πr²h?
A cone with the same base and height as a cylinder has one-third of the cylinder’s volume.
What is the difference between lateral area and total surface area?
Lateral area covers only the curved side, while total surface area adds the circular base.
Can radius and height be decimals?
Yes. The formulas work for any positive real measurements.
How can I check the total surface area?
First find slant height, then compute πrl for the side and add πr² for the base.
What if I already know the slant height?
Use a more specific cone calculator for that situation, or recover the missing dimension with the Pythagorean relationship if the other measurement is known.