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Finding the Fourth Proportional to 721.21, 1,076.55 and 619.15

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Solution

The fourth proportional to 721.21, 1,076.55 and 619.15 is: 924.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    721.21 : 1,076.55 = 619.15 : x
  2. Step 2: Convert to fraction form
    721.21/1,076.55 = 619.15/x
  3. Step 3: Cross multiply
    721.21x = 1,076.55 × 619.15
  4. Step 4: Simplify right side
    721.21x = 666,545.93
  5. Step 5: Solve for x
    x = 666,545.93/721.21
  6. Step 6: Final answer
    x = 924.21

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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.