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Finding the Fourth Proportional to 1,038.40, 1,558.20 and 389.58

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Solution

The fourth proportional to 1,038.40, 1,558.20 and 389.58 is: 584.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,038.40 : 1,558.20 = 389.58 : x
  2. Step 2: Convert to fraction form
    1,038.40/1,558.20 = 389.58/x
  3. Step 3: Cross multiply
    1,038.40x = 1,558.20 × 389.58
  4. Step 4: Simplify right side
    1,038.40x = 607,043.56
  5. Step 5: Solve for x
    x = 607,043.56/1,038.40
  6. Step 6: Final answer
    x = 584.60

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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.