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Finding the Fourth Proportional to 938.39, 1,405.15 and 646.79

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Solution

The fourth proportional to 938.39, 1,405.15 and 646.79 is: 968.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.39 : 1,405.15 = 646.79 : x
  2. Step 2: Convert to fraction form
    938.39/1,405.15 = 646.79/x
  3. Step 3: Cross multiply
    938.39x = 1,405.15 × 646.79
  4. Step 4: Simplify right side
    938.39x = 908,828.33
  5. Step 5: Solve for x
    x = 908,828.33/938.39
  6. Step 6: Final answer
    x = 968.50

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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.