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Finding the Fourth Proportional to 1,378.72, 2,068.16 and 391.62

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Solution

The fourth proportional to 1,378.72, 2,068.16 and 391.62 is: 587.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.72 : 2,068.16 = 391.62 : x
  2. Step 2: Convert to fraction form
    1,378.72/2,068.16 = 391.62/x
  3. Step 3: Cross multiply
    1,378.72x = 2,068.16 × 391.62
  4. Step 4: Simplify right side
    1,378.72x = 809,932.82
  5. Step 5: Solve for x
    x = 809,932.82/1,378.72
  6. Step 6: Final answer
    x = 587.45

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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.