Continuing westward, Mars formed a different type of isosceles triangle with Pollux and Castor on Feb. 2, with Pollux marking the vertex and Mars and Castor forming the base.

An isosceles triangle has 2 sides of equal length. The dashes on the lines show they are equal in length. The angles at the base of the equal sides are equal.

An isosceles triangle has two sides of the same length (25 cm). The perpendicular height is the height at a right angle to the base of the triangle.

Daniel Buchanan, Oscillations Near an Isosceles-Triangle Solution of the Problem of Three Bodies as the Finite Masses Become Unequal, American Journal of Mathematics, Vol. 39, No. 1 (Jan., 1917), pp.