Answer:
The correct option is;
A. 30
Step-by-step explanation:
Given that the perpendicular bisector forms two other right angled triangles, we have;
For the larger right angled triangle, hypotenuse length = 100
For the smaller right angled triangle, hypotenuse length = 90
We note that;
y² = x² + 10²
z² = x² + 90²
100² = z² + y ²
Therefore we have;
100² = x² + 10² + z² = x² + 10² + x² + 90² = 2·x² + 90² + 10²
10000 = 2·x² + 8200
2·x² = 10000 - 8200 = 1800
x² = 1800/2 = 900
x = 30
