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Finding the Fourth Proportional to 390.96, 586.90 and 389.20

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Solution

The fourth proportional to 390.96, 586.90 and 389.20 is: 584.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.96 : 586.90 = 389.20 : x
  2. Step 2: Convert to fraction form
    390.96/586.90 = 389.20/x
  3. Step 3: Cross multiply
    390.96x = 586.90 × 389.20
  4. Step 4: Simplify right side
    390.96x = 228,421.48
  5. Step 5: Solve for x
    x = 228,421.48/390.96
  6. Step 6: Final answer
    x = 584.26

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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.