An isosceles triangle has a perimeter of 36 centimetres and a base of 10 centimetres. How long is each of its two equal sides?

الشرح

Removing the base leaves 26 cm for the two matching sides together, and because they are equal each takes half of that. Keeping the whole 26 as a single side would make the three sides total 62, far beyond the perimeter the triangle was given.