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Finding the Fourth Proportional to 1,079.89, 1,490.02 and 686.77

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Solution

The fourth proportional to 1,079.89, 1,490.02 and 686.77 is: 947.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,079.89 : 1,490.02 = 686.77 : x
  2. Step 2: Convert to fraction form
    1,079.89/1,490.02 = 686.77/x
  3. Step 3: Cross multiply
    1,079.89x = 1,490.02 × 686.77
  4. Step 4: Simplify right side
    1,079.89x = 1,023,301.04
  5. Step 5: Solve for x
    x = 1,023,301.04/1,079.89
  6. Step 6: Final answer
    x = 947.60

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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.