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Finding the Fourth Proportional to 720.61, 992.37 and 687.81

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Solution

The fourth proportional to 720.61, 992.37 and 687.81 is: 947.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.61 : 992.37 = 687.81 : x
  2. Step 2: Convert to fraction form
    720.61/992.37 = 687.81/x
  3. Step 3: Cross multiply
    720.61x = 992.37 × 687.81
  4. Step 4: Simplify right side
    720.61x = 682,562.01
  5. Step 5: Solve for x
    x = 682,562.01/720.61
  6. Step 6: Final answer
    x = 947.20

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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.