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Finding the Fourth Proportional to 947.12, 1,420.83 and 485.21

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Solution

The fourth proportional to 947.12, 1,420.83 and 485.21 is: 727.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.12 : 1,420.83 = 485.21 : x
  2. Step 2: Convert to fraction form
    947.12/1,420.83 = 485.21/x
  3. Step 3: Cross multiply
    947.12x = 1,420.83 × 485.21
  4. Step 4: Simplify right side
    947.12x = 689,393.82
  5. Step 5: Solve for x
    x = 689,393.82/947.12
  6. Step 6: Final answer
    x = 727.89

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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.