Equal side and base
Equal side a + Base b
h = √(a²−b²/4); A = bh/2
Open calculator ↗GEOMETRY, ONE FIGURE AT A TIMEIsosceles triangle.
Isosceles triangle.
Understand every measure.
Find the balance in two equal sides. Four free tools, clear formulas and a little discovery along the way.
Find your calculator ↗FIGURE 052D / REFERENCE DRAWING
ISOSCELES TRIANGLENOT TO SCALE
THE CALCULATOR DESK
Start with what you know.
4 calculators available
Base and height
Base b + Height h
a = √(h²+b²/4)
Open calculator ↗Equal side and vertex angle
Equal side a + Vertex angle θ
b = 2a sin(θ/2)
Open calculator ↗Perimeter and base
Perimeter P + Base b
a = (P−b)/2; P > 2b
Open calculator ↗MEET THE FIGURE
A isosceles triangle, explained.
An isosceles triangle has at least two equal sides. Here a denotes each of the equal sides and b denotes the selected base. This inclusive definition allows an equilateral triangle as a special case.
Understand the properties ↗LOOK A LITTLE CLOSER
More than a formula.
Its line of symmetry passes through the vertex and the midpoint of the base.
Vertex angle means the angle between the equal sides. The base is not necessarily the longest side.
Explore three geometry facts ↗These tools use ideal Euclidean geometry. Every input must use the same unit. Numerical results are rounded and do not replace measurement, specialist design or safety checks. See worked examples.