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Finding the Fourth Proportional to 783.78, 1,081.68 and 489.22

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Solution

The fourth proportional to 783.78, 1,081.68 and 489.22 is: 675.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    783.78 : 1,081.68 = 489.22 : x
  2. Step 2: Convert to fraction form
    783.78/1,081.68 = 489.22/x
  3. Step 3: Cross multiply
    783.78x = 1,081.68 × 489.22
  4. Step 4: Simplify right side
    783.78x = 529,179.49
  5. Step 5: Solve for x
    x = 529,179.49/783.78
  6. Step 6: Final answer
    x = 675.16

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.