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Finding the Fourth Proportional to 691.20, 1,036.78 and 656.59

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Solution

The fourth proportional to 691.20, 1,036.78 and 656.59 is: 984.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.20 : 1,036.78 = 656.59 : x
  2. Step 2: Convert to fraction form
    691.20/1,036.78 = 656.59/x
  3. Step 3: Cross multiply
    691.20x = 1,036.78 × 656.59
  4. Step 4: Simplify right side
    691.20x = 680,739.38
  5. Step 5: Solve for x
    x = 680,739.38/691.20
  6. Step 6: Final answer
    x = 984.87

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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.