Final answer:
To find the area of a circle with a diameter of 8 cm, Mark can use the formula A = πr² or A = ½πd² by substituting the radius or diameter into the formulas.
Step-by-step explanation:
To find the area of a circle, Mark can use the formula A = πr², where A is the area and r is the radius of the circle. Since the diameter is given, he can find the radius by dividing the diameter by 2. So, the radius would be 8 cm ÷ 2 = 4 cm. Plugging this into the formula, Mark can use the expression A = π(4 cm)² to find the area of the circle. Another expression he can use is A = π(8 cm)² / 4, by substituting the diameter directly into the formula. Finally, Mark can also use A = ½π(8 cm)² by using the formula for the area of a circle in terms of diameter.
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