Question

about 10 cm shorter than 20 cm about 20 cm longer than 20 cm

Explanation:

Step1: Observe the purple bar length

The purple bar is about 10 cm.

Step2: Compare with the orange bar

The orange bar is longer than the purple bar but clearly shorter than 20 cm (since 10 cm is half of 20 cm and the orange bar is not double - the length of the purple bar).

Answer:

Shorter than 20 cm