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Finding the Fourth Proportional to 818.64, 1,228.16 and 385.70

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Solution

The fourth proportional to 818.64, 1,228.16 and 385.70 is: 578.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.64 : 1,228.16 = 385.70 : x
  2. Step 2: Convert to fraction form
    818.64/1,228.16 = 385.70/x
  3. Step 3: Cross multiply
    818.64x = 1,228.16 × 385.70
  4. Step 4: Simplify right side
    818.64x = 473,696.14
  5. Step 5: Solve for x
    x = 473,696.14/818.64
  6. Step 6: Final answer
    x = 578.64

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.