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Finding the Fourth Proportional to 985.82, 1,478.57 and 641.60

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Solution

The fourth proportional to 985.82, 1,478.57 and 641.60 is: 962.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.82 : 1,478.57 = 641.60 : x
  2. Step 2: Convert to fraction form
    985.82/1,478.57 = 641.60/x
  3. Step 3: Cross multiply
    985.82x = 1,478.57 × 641.60
  4. Step 4: Simplify right side
    985.82x = 948,639.91
  5. Step 5: Solve for x
    x = 948,639.91/985.82
  6. Step 6: Final answer
    x = 962.29

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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.