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Finding the Fourth Proportional to 985.18, 1,478.43 and 408.05

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Solution

The fourth proportional to 985.18, 1,478.43 and 408.05 is: 612.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.18 : 1,478.43 = 408.05 : x
  2. Step 2: Convert to fraction form
    985.18/1,478.43 = 408.05/x
  3. Step 3: Cross multiply
    985.18x = 1,478.43 × 408.05
  4. Step 4: Simplify right side
    985.18x = 603,277.06
  5. Step 5: Solve for x
    x = 603,277.06/985.18
  6. Step 6: Final answer
    x = 612.35

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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.