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Finding the Fourth Proportional to 1,212.28, 1,818.72 and 390.53

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Solution

The fourth proportional to 1,212.28, 1,818.72 and 390.53 is: 585.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.28 : 1,818.72 = 390.53 : x
  2. Step 2: Convert to fraction form
    1,212.28/1,818.72 = 390.53/x
  3. Step 3: Cross multiply
    1,212.28x = 1,818.72 × 390.53
  4. Step 4: Simplify right side
    1,212.28x = 710,269.27
  5. Step 5: Solve for x
    x = 710,269.27/1,212.28
  6. Step 6: Final answer
    x = 585.90

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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.