Final answer:
The rate of discount for the microwave oven is 21.89%.
Step-by-step explanation:
The rate of discount can be found by subtracting the discount from the original price and dividing it by the original price, then multiplying by 100 to get the percentage.
Original price = P5,190
Discount = P1,137.50
Rate of discount = (Discount / Original price) * 100 = (P1,137.50 / P5,190) * 100 = 21.89
Therefore, the rate of discount is 21.89%.