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Finding the Fourth Proportional to 1,018.91, 1,405.17 and 686.72

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Solution

The fourth proportional to 1,018.91, 1,405.17 and 686.72 is: 947.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,018.91 : 1,405.17 = 686.72 : x
  2. Step 2: Convert to fraction form
    1,018.91/1,405.17 = 686.72/x
  3. Step 3: Cross multiply
    1,018.91x = 1,405.17 × 686.72
  4. Step 4: Simplify right side
    1,018.91x = 964,958.34
  5. Step 5: Solve for x
    x = 964,958.34/1,018.91
  6. Step 6: Final answer
    x = 947.05

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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.