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Finding the Fourth Proportional to 385.64, 578.48 and 321.40

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Solution

The fourth proportional to 385.64, 578.48 and 321.40 is: 482.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.64 : 578.48 = 321.40 : x
  2. Step 2: Convert to fraction form
    385.64/578.48 = 321.40/x
  3. Step 3: Cross multiply
    385.64x = 578.48 × 321.40
  4. Step 4: Simplify right side
    385.64x = 185,923.47
  5. Step 5: Solve for x
    x = 185,923.47/385.64
  6. Step 6: Final answer
    x = 482.12

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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.