remember that to put a number in scientific notation is necessary to have the first digit of the number different to 0, so
to calculate the order of magnitude, if the number is greater than 3.16, we assume it as a 10, so in this case as 7.654 > 3.16 we get that the order is
So the figure is called a ray. Which is when there’s a point and than an arrow extends off that point forever. But the way to write a ray is by putting an arrow above it.