1. Identify the shape of each figure and recall the formula for surface area.
2. For a rectangular prism, the surface area is calculated using the formula: 2(lw + lh + wh), where l is length, w is width, and h is height.
3. For the first figure (a), the dimensions are 22 m, 16 m, and 8 m.
- Surface area = 2(22×16 + 22×8 + 16×8) = 2(352 + 176 + 128) = 2(656) = 1312 m².
4. For the second figure (b), the dimensions are 13 cm, 19 cm, and 21 cm.
- Surface area = 2(13×19 + 13×21 + 19×21) = 2(247 + 273 + 399) = 2(919) = 1838 cm².
5. For the third figure (c), the dimensions are 45 mm, 100 mm, and 100 mm.
- Surface area = 2(45×100 + 45×100 + 100×100) = 2(4500 + 4500 + 10000) = 2(19000) = 38000 mm².
6. For the fourth figure (d), the shape is an irregular prism made of two rectangular prisms. The surface area is the sum of the areas of all faces.
- The total surface area is calculated by summing the areas of all visible faces, considering the overlapping faces are not counted twice.
- The total surface area is 1800 m².
7. For the fifth problem (e), the bar of soap has dimensions 20 mm, 34 mm, and 10 mm.
- Surface area = 2(20×34 + 20×10 + 34×10) = 2(680 + 200 + 340) = 2(1220) = 2440 mm².
8. For the sixth problem (f), the television has dimensions 120 cm, 68 cm, and 14 cm.
- Surface area = 2(120×68 + 120×14 + 68×14) = 2(8160 + 1680 + 952) = 2(10792) = 21584 cm².
Final Answers:
a. 1312 m²
b. 1838 cm²
c. 38000 mm²
d. 1800 m²
e. 2440 mm²
f. 21584 cm²
Parent Tip: Review the logic above to help your child master the concept of surface area worksheet printable.
