Three points are given on the straight line. A, B and C, with AB = 13 cm, AC = 4 cm. Find the length of the segment BC.

| May 13, 2021 | education

According to the condition of the assignment, three points A, B and C are given on the straight line. The values ​​of the segments AB = 13 cm and AC = 4 cm are given. It is necessary to find the length of the segment BC.

The first solution
Let points B and C be located to the right of point A.
All points will lie on a straight line in the following order: A, C, B, since the segments AB and AC are laid off from one point A in one direction and the segment AB is larger than the segment AC.
The size of the segment BC, and in this case it will be correctly called CB without changing the size, is equal to the difference between the lengths of the segments AB and AC: BC = AB – AC.
BC = 13 – 4 = 9 cm.

Second solution
Let points B and C be located on both sides of point A: let’s say segment AC is laid to the right, and segment AB is to the left.
Then, the points will be located sequentially: B, A and C.
The length of the segment BC will be the sum of the lengths of the segments AB and AC: BC = AB + AC.
BC = 13 + 4 = 17 cm.
Answer: the length of the segment BC is 9 cm (the points lie on a straight line in the following order: A, C, B);

the length of the segment BC is 17 cm (the points are located sequentially: B, A and C).



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