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Finding the Fourth Proportional to 985.12, 1,477.90 and 408

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Solution

The fourth proportional to 985.12, 1,477.90 and 408 is: 612.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.12 : 1,477.90 = 408 : x
  2. Step 2: Convert to fraction form
    985.12/1,477.90 = 408/x
  3. Step 3: Cross multiply
    985.12x = 1,477.90 × 408
  4. Step 4: Simplify right side
    985.12x = 602,983.20
  5. Step 5: Solve for x
    x = 602,983.20/985.12
  6. Step 6: Final answer
    x = 612.09

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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.