Introduction about Geometric surface area: Surface area is the measure of how much exposed area a solid object has, expressed in square units. For polyhedra the surface area is the sum of the areas of its faces. Smooth surfaces, such as a sphere, are assigned surface area using their representation as parametric surfaces. Let us see how to calculate surface area of some geometric basic shapes. (Source – Wikipedia) Geometric Formula to Find the Surface Area: Surface area of the sphere (A) = 4 p r2 square unit A- Surface area. r- Radius Surface area (A) = 2(wh + lw + lh) square units w – Width h – Height l – Length Surface area of cylinder (SA) = 2 p r2 + 2 p r h square units r – Radius h – Height Surface area of cone (SA) = p r s + p r2 square units r – Radius s – Slant height Geometric Surface Area – Example Problems: The sphere has radius of 6.7 cm. Find the surface area and volume of sphere. Solution: Given: Radius (r) = 6.7 cm Geometric Formula: Surface area of the sphere (A) = 4 p r2 square unit = 4 x p x 6.7 2 = 4 x 3.14 x 44.89 Surface area of the sphere (A) = 563.8184 cm2 2. The cylinder has the radius r= 6 cm, h= 17 cm. Find the surface area of cylinder. Solution: Given: r= 6 cm h=17 cm Geometric Formula: The surface area of the cylinder = 2 p r2 + 2 p r h square units = 2 x 3.14 x 62 + 2 x 3.14 x 6 x 17 = 226.08 + 640.56 The surface area of the cylinder = 640.56 cm2 3. The cone has the radius = 6 cm and slant height = 17 cm. Find the surface area of the cone. Solution: Given: Radius (r) = 6 cm Slant Height (s) =17 cm Geometric Formula: The surface area of the cone = p r s + p r2 square units = 3.14 x 6 x 17+ 3.14 x 62 = 320.28 + 113.04 = 433.32 The surface area of the cone = 433.32 cm2 4. The rectangular prism has the length 10 cm, width 5 cm and height 3 cm. find the surface area of the rectangular prism. Solution: Given: Length (l) = 10 cm Width (w) = 5 cm Height (h) = 3 cm Geometric Formula: Surface area (A) = 2(wh + lw + lh) square units = 2 (5 x 3 + 10 x 5 + 10 x 3) = 2 (15 + 50 + 30) = 2 (95) Surface area (A) = 190 cm2 Know more Area of a Sector Formula i found this interesting link What is an Angle
Related Articles -
Geometric, surface, area,
|