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Finding the Fourth Proportional to 385.64, 531.68 and 280.64

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Solution

The fourth proportional to 385.64, 531.68 and 280.64 is: 386.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.64 : 531.68 = 280.64 : x
  2. Step 2: Convert to fraction form
    385.64/531.68 = 280.64/x
  3. Step 3: Cross multiply
    385.64x = 531.68 × 280.64
  4. Step 4: Simplify right side
    385.64x = 149,210.68
  5. Step 5: Solve for x
    x = 149,210.68/385.64
  6. Step 6: Final answer
    x = 386.92

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.