Question

Fix the two words that are used incorrectly.

In one famous optical allusion, two circles of the same size are surrounded
by images that trick the viewer into seeing one circle as larger then the
other.

Answer 1

Allusion needs to be changed to illusion and then needs to be changed to than.

Step-by-step explanation:

An "allusion" is an expression designed to call something to mind without mentioning it explicitly. An "illusion" is something that is likely to be wrongly perceived by the senses.

The use of "then" indicates time, while "than" is used for comparisons.

Hope this helps!