We don't have a precise measurement for the temperature of Mars' inner core. However, scientists estimate it to be around 1,500-1,800 degrees Celsius (2,732-3,272 degrees Fahrenheit).

Here's why this is just an estimate:

* No direct measurements: We can't directly measure the inner core temperature.

* Indirect methods: Scientists use indirect methods like seismic waves and models based on the planet's size, density, and composition to infer the core temperature.

* Uncertainty: These methods are subject to some uncertainty, and therefore the estimated temperature range.

It's worth noting that this estimated temperature is significantly cooler than Earth's inner core, which is estimated to be around 5,200 degrees Celsius (9,392 degrees Fahrenheit). This difference is likely due to Mars' smaller size and less active geological processes.