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Finding the Fourth Proportional to 981.47, 1,354.77 and 687.60

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Solution

The fourth proportional to 981.47, 1,354.77 and 687.60 is: 949.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.47 : 1,354.77 = 687.60 : x
  2. Step 2: Convert to fraction form
    981.47/1,354.77 = 687.60/x
  3. Step 3: Cross multiply
    981.47x = 1,354.77 × 687.60
  4. Step 4: Simplify right side
    981.47x = 931,539.85
  5. Step 5: Solve for x
    x = 931,539.85/981.47
  6. Step 6: Final answer
    x = 949.12

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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.