How this calculator works
Rearrange the triangle area equation to isolate the base. The height must be perpendicular to the line containing that base, even if its foot falls outside the triangle. The table holds area fixed and varies the chosen base: doubling it halves the required height. These pairs describe possible triangles, not a unique set of remaining side lengths.
Formula
K = bh/2; b = 2K/h; h = 2K/b. At fixed area, b′ = kb and h′ = h/k.
Worked example
Area 30 m² and height 6 m give b = 60/6 = 10 m. The same area can be obtained from a base of 20 m and a perpendicular height of 3 m.
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Frequently asked questions
Which side is the base?
Any side can be chosen as the base if its matching perpendicular height is used.
Can I enter zero height?
No. A positive-area triangle needs positive base and height, and the reverse formulas divide by those lengths.
Do area and height determine the entire triangle?
No. They fix the base length but the top vertex can move along a line parallel to that base without changing area.