The perimeter of an isosceles triangle is 28 cm and the lateral side is 10 cm, find the base of the triangle.

Recall that an isosceles triangle has equal sides. Then in our triangle, the first side is 10, and the second side is also 10 cm, let x be the base of the triangle, and the perimeter is 28 cm.Since the perimeter of the triangle is equal to the sum of all its sides, we can write the equation: x + 10 + 10 = 28. Let’s transfer to one part all the unknown terms of the equation, and to the other all the known terms: x = 28 -10 – 10, x = 28 – 20, x = 8.
Answer: the base is 8 cm.