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Finding the Fourth Proportional to 762.81, 1,145.03 and 642.39

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Solution

The fourth proportional to 762.81, 1,145.03 and 642.39 is: 964.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    762.81 : 1,145.03 = 642.39 : x
  2. Step 2: Convert to fraction form
    762.81/1,145.03 = 642.39/x
  3. Step 3: Cross multiply
    762.81x = 1,145.03 × 642.39
  4. Step 4: Simplify right side
    762.81x = 735,552.61
  5. Step 5: Solve for x
    x = 735,552.61/762.81
  6. Step 6: Final answer
    x = 964.27

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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.