a regular prism with a pentagonal base has a height of 12cm. the apothem of the base measures 2.75cm and its sides, 4cm. What is the total area of the prism?
Q. a regular prism with a pentagonal base has a height of 12cm. the apothem of the base measures 2.75cm and its sides, 4cm. What is the total area of the prism?
Calculate Perimeter: To find the total area of the prism, we need to calculate the lateral area and the area of the two pentagonal bases. The lateral area (LA) of a prism is given by the perimeter P of the base times the height h of the prism. The perimeter of a pentagonal base is the sum of the lengths of its five sides.Calculation: P=5×side_length=5×4cm=20cm
Calculate Lateral Area: Now we calculate the lateral area using the perimeter and the height of the prism.Calculation: LA=P×h=20cm×12cm=240cm2
Calculate Base Area: Next, we need to calculate the area of one pentagonal base. The area A of a regular pentagon can be calculated using the formula A=21⋅P⋅a, where P is the perimeter and a is the apothem.Calculation: A=21⋅P⋅a=21⋅20cm⋅2.75cm=27.5cm2
Calculate Total Base Area: Since the prism has two identical pentagonal bases, we need to multiply the area of one base by 2 to get the total area of both bases.Calculation: Total area of both bases = A×2=27.5cm2×2=55cm2
Calculate Total Surface Area: Finally, we add the lateral area and the total area of the two bases to find the total surface area of the prism.Calculation: Total surface area = LA+Total area of both bases=240cm2+55cm2=295cm2
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