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Finding the Fourth Proportional to 390.48, 584.45 and 287.72

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Solution

The fourth proportional to 390.48, 584.45 and 287.72 is: 430.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.48 : 584.45 = 287.72 : x
  2. Step 2: Convert to fraction form
    390.48/584.45 = 287.72/x
  3. Step 3: Cross multiply
    390.48x = 584.45 × 287.72
  4. Step 4: Simplify right side
    390.48x = 168,156.52
  5. Step 5: Solve for x
    x = 168,156.52/390.48
  6. Step 6: Final answer
    x = 430.64

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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.