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Finding the Fourth Proportional to 985.53, 1,478.31 and 408.81

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Solution

The fourth proportional to 985.53, 1,478.31 and 408.81 is: 613.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.53 : 1,478.31 = 408.81 : x
  2. Step 2: Convert to fraction form
    985.53/1,478.31 = 408.81/x
  3. Step 3: Cross multiply
    985.53x = 1,478.31 × 408.81
  4. Step 4: Simplify right side
    985.53x = 604,347.91
  5. Step 5: Solve for x
    x = 604,347.91/985.53
  6. Step 6: Final answer
    x = 613.22

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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.