Regular Triangular Pyramid Guide
A regular triangular pyramid has an equilateral triangle as its base. Its apex sits above the center of that triangle. Because the base sides are equal, the three side faces match. This shape is also called a regular tetrahedral style pyramid when all four faces are equilateral. Many classroom tasks use a regular triangular pyramid because it links area, height, and three dimensional reasoning.
Why Surface Area Matters
Surface area tells how much outside material covers the pyramid. It is useful for wrapping, painting, coating, design models, and geometry checks. The total surface area includes one triangular base and three equal triangular faces. The lateral area includes only the three side faces. This calculator shows both values, so you can choose the correct answer for the problem.
Measurements You Can Enter
You always need the base side length. You can then enter either the slant height or the vertical height. The slant height runs from the apex to the midpoint of a base edge. The vertical height runs from the apex straight down to the base center. The calculator can convert between these values using the base inradius. It also finds volume, base perimeter, face area, and lateral edge length.
Study And Work Uses
This tool helps when a diagram gives different measurements. Some problems give slant height. Others give vertical height. Some projects also need a cost estimate. For that reason, this page includes count, waste rate, and cost fields. They help estimate total material area and price. You can leave those optional fields at zero when you only need geometry.
Accuracy Tips
Use one measurement unit for every length. Do not mix inches with feet unless you convert first. Pick a sensible decimal precision. Higher precision is useful for checking formulas. Lower precision is better for reports. When using slant height, it must be longer than the base inradius. Otherwise, the vertical height cannot exist. After calculating, compare the example table and formulas. This makes errors easier to spot.
The export buttons save the finished work. CSV is useful for spreadsheets. PDF is useful for notes, submissions, and printed records. Keep the saved file with your source measurements for careful later review and auditing.