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Finding the Fourth Proportional to 390.32, 584.80 and 281.60

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Solution

The fourth proportional to 390.32, 584.80 and 281.60 is: 421.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.32 : 584.80 = 281.60 : x
  2. Step 2: Convert to fraction form
    390.32/584.80 = 281.60/x
  3. Step 3: Cross multiply
    390.32x = 584.80 × 281.60
  4. Step 4: Simplify right side
    390.32x = 164,679.68
  5. Step 5: Solve for x
    x = 164,679.68/390.32
  6. Step 6: Final answer
    x = 421.91

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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.