If line segment BC=80, and line segment AC=89. then line segment AB=________?

Question

If line segment BC=80, and line segment AC=89. then line segment AB=________?

Answer 1

This question is missing information. It tells us that:

BC = 80

AC = 89

and asks for AB = ?

But with only two side lengths, we usually cannot find the third side unless we know something else such as that the triangle is a right triangle or the points are on a straight line. If this is a right triangle and AC is the hypotenuse, then we can use the Pythagorean theorem:

AB² + BC² = AC²

Since we know that BC = 80 and AC = 89, we can plug in those values into pythagorean theorem to find AB:

AB² + 80² = 89²

AB² + 6400 = 7921

AB² = 1521

AB = 39

So, if it is a right triangle and AC is the hypotenuse, then AB = 39. But without knowing it is a right triangle, the answer is not enough information. Different triangles could have sides 80 and 89, but different possible values for AB.

Answer 2

Like Mark was saying, given this context it is difficult to say a distance if we do not know the position of A in relation to BC. If it's a straight line, then its just the two distances added. If it is somewhere else in the plane, we need more information. Hope that helps.