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Finding the Fourth Proportional to 393.42, 586.65 and 389.90

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Solution

The fourth proportional to 393.42, 586.65 and 389.90 is: 581.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    393.42 : 586.65 = 389.90 : x
  2. Step 2: Convert to fraction form
    393.42/586.65 = 389.90/x
  3. Step 3: Cross multiply
    393.42x = 586.65 × 389.90
  4. Step 4: Simplify right side
    393.42x = 228,730.44
  5. Step 5: Solve for x
    x = 228,730.44/393.42
  6. Step 6: Final answer
    x = 581.40

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.