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Finding the Fourth Proportional to 687.08, 1,030.62 and 321.79

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Solution

The fourth proportional to 687.08, 1,030.62 and 321.79 is: 482.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.08 : 1,030.62 = 321.79 : x
  2. Step 2: Convert to fraction form
    687.08/1,030.62 = 321.79/x
  3. Step 3: Cross multiply
    687.08x = 1,030.62 × 321.79
  4. Step 4: Simplify right side
    687.08x = 331,639.42
  5. Step 5: Solve for x
    x = 331,639.42/687.08
  6. Step 6: Final answer
    x = 482.68

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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.