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Finding the Fourth Proportional to 1,378.89, 2,068.07 and 638.47

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Solution

The fourth proportional to 1,378.89, 2,068.07 and 638.47 is: 957.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.89 : 2,068.07 = 638.47 : x
  2. Step 2: Convert to fraction form
    1,378.89/2,068.07 = 638.47/x
  3. Step 3: Cross multiply
    1,378.89x = 2,068.07 × 638.47
  4. Step 4: Simplify right side
    1,378.89x = 1,320,400.65
  5. Step 5: Solve for x
    x = 1,320,400.65/1,378.89
  6. Step 6: Final answer
    x = 957.58

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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.