Δabc is a right triangle in which is a right angle, ab = 1, ac = 2, and bc = .

We are asked to solve for the measurement of side BC in the given right triangle ΔABC and other side measurements were also given such as AB=1 and AC = 2. Since this is a right triangle, we can use and apply the Pythagorean theorem c²= a² + b² and the solution is shown below:
c = AC
b = BC
a = AB
AC² = AB² + BC² , substitute values we have:
2² = 1² + BC²
BC² = 4-1
BC = √3
BC = 1.732

The answer for the length of BC is 1.732 units.