# Can a Triangle have 1 right angle and 3 equal sides?

If an ordinary planar triangle is equilateral (having equal sides), then it will also be equiangular (having equal angles) and those angles will sum to $\pi$ radians (${180}^{\circ}$), so each internal angle will be $\frac{\pi}{3}$ radians (${60}^{\circ}$).
On the other hand a curvilinear triangle on the surface of a sphere could have $3$ right angles and $3$ equal sides if the length of each side is $\frac{1}{4}$ of the circumference of the sphere.