one astronomical units is about 1.5 X 10 km .

An astronomical unit is a unit of length equal to about 149,597,8701 kilometres (92,955,807.3 mi) or approximately the mean Earth–Sun distance.

What is your question?

1 AU = 149,597,871 km

Assuming that what you want is the missing exponent:

One astronomical units is about
1.5 X 10^8 km

Actually, one astronomical unit (AU) is defined as the average distance between the Earth and the Sun. It is used as a convenient unit of measurement in space to give a sense of scale.

As of current measurements, one astronomical unit is approximately equal to 149.6 million kilometers or about 93 million miles.

To calculate this value, you can use the following conversion factor:

1 astronomical unit (AU) = 149.6 million kilometers

To convert this into scientific notation, you can represent 149.6 million as 1.496 × 10^8 kilometers. So, the correct value is about 1.496 × 10^8 km.