We know that,
Area of rectangle = Length × Breadth
Area of 1st rectangle = p × q = pq
Area of 2nd rectangle = 10m × 5n = 10 × 5 × m × n = 50 mn
Area of 3rd rectangle = 20x2 × 5y2 = 20 × 5 × x2 × y2 = 100 x2y2
Area of 4th rectangle = 4x × 3x2 = 4 × 3 × x × x2 = 12x3
Area of 5th rectangle = 3mn × 4np = 3 × 4 × m × n × n × p = 12mn2p