for irregular shapes, simply cut the shapes into recognizable shapes like square, rectangle, triangle. Solve the area of each shape and add it up to get the total area of the irregular shape.
1) rectangle 1 = 5cm 3cm = 15cm²
rectangle 2 = 2cm 4cm = 8cm²
15cm² + 8cm² = 23 cm²
2) rectangle 1 = 9cm (10cm-6cm) = 9cm 4cm = 36cm²
rectangle 2 = 6cm 2cm = 12cm²
36cm² + 12cm² = 48cm²
3) square 1 = (2cm)² = 4cm²
square 2 = (4cm)² = 16cm²
shaded area only. subtraction performed.
16cm² - 4cm² = 12cm²
4) square = (10cm)² = 100cm
triangle = (10cm 10cm)/2 = 100cm² / 2 = 50cm²
100cm² + 50cm² = 150cm²
5) rectangle 1 = 4mm 3mm = 12mm²
rectangle 2 = 8mm 10mm = 80mm²
12mm² + 80mm² = 92mm²
