Which property would you use to find an equivalent expression for 9 x 10?

Determine the number of outcomes in the event. decide whether the event is a simple event or not. upper a computer is used to select randomly a number between 1 and 9 comma inclusive. event upper b is selecting a number greater than 4. event upper b has nothing outcome(s). is the event a simple event? (yes or no) because event upper b has (fewer than, exactly, more than) one outcome.

Extra points! find the missing dimension! need asap

Which geometric principle is used to justify the construction below?