Two sides of a triangle are 10 mm and 7 mm. Determine the length of the third side from the choices given.

A) 2 mm
B) 5 mm
C) 1 mm
D) 20 mm

1 answer

To determine the possible length of the third side of the triangle, we can use the triangle inequality theorem.

According to the triangle inequality theorem, the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Therefore, the possible range of lengths for the third side of the triangle with sides 10 mm and 7 mm would be:
7 + 10 > x
17 > x

However, the third side cannot be longer than the sum of the other two sides. So the third side must also be less than the difference between the two given sides:
10 - 7 < x
3 < x

Therefore, the possible lengths for the third side range from 3 to 17 mm. From the choices given, the closest answer is B) 5 mm.