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Finding the Fourth Proportional to 1,320.68, 1,981.20 and 551

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Solution

The fourth proportional to 1,320.68, 1,981.20 and 551 is: 826.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,320.68 : 1,981.20 = 551 : x
  2. Step 2: Convert to fraction form
    1,320.68/1,981.20 = 551/x
  3. Step 3: Cross multiply
    1,320.68x = 1,981.20 × 551
  4. Step 4: Simplify right side
    1,320.68x = 1,091,641.20
  5. Step 5: Solve for x
    x = 1,091,641.20/1,320.68
  6. Step 6: Final answer
    x = 826.58

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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.