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Finding the Fourth Proportional to 405.60, 609.30 and 390.30

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Solution

The fourth proportional to 405.60, 609.30 and 390.30 is: 586.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.60 : 609.30 = 390.30 : x
  2. Step 2: Convert to fraction form
    405.60/609.30 = 390.30/x
  3. Step 3: Cross multiply
    405.60x = 609.30 × 390.30
  4. Step 4: Simplify right side
    405.60x = 237,809.79
  5. Step 5: Solve for x
    x = 237,809.79/405.60
  6. Step 6: Final answer
    x = 586.32

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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.