Answer:

1. 39 dm²

Solution:

A = LW – LW

A = (10 dm × 6dm) – (7dm × 3dm)

A = 60 dm² – 21 dm²

A = 39 dm²

2. 90 m²

Solution:

A =

A =

A = 9m(6m) + 36m²

A = 54 m² + 36m²

A = 90 m²

3. 100.26 cm²

Solution:

A =

A = (12cm × 6cm) + 3.14(3 cm)²/2 + 3.14(3 cm)²/2

A = 72 cm² + 14.13 cm² +14.13 cm²

A = 100.26 cm²

4. 49.04 m²

Solution:

A =

A = 3 14(6m)² – (8m)²

A = 3.14(36 m²) – 64 m²

A = 113.04 m² – 64 m²

A = 49.04 m²

5. 72 m²

Solution:

A = LW – 1/2bh

A = (13 m × 8m) – 1/2(8m × 8m)

A = 104 m² – 1/2(64 m²)

A = 104 m² – 32 m²

A = 72 m²