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Finding the Fourth Proportional to 979.78, 1,352.01 and 686.02

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Solution

The fourth proportional to 979.78, 1,352.01 and 686.02 is: 946.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.78 : 1,352.01 = 686.02 : x
  2. Step 2: Convert to fraction form
    979.78/1,352.01 = 686.02/x
  3. Step 3: Cross multiply
    979.78x = 1,352.01 × 686.02
  4. Step 4: Simplify right side
    979.78x = 927,505.90
  5. Step 5: Solve for x
    x = 927,505.90/979.78
  6. Step 6: Final answer
    x = 946.65

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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.