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Finding the Fourth Proportional to 947.10, 1,420.65 and 807.90

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Solution

The fourth proportional to 947.10, 1,420.65 and 807.90 is: 1,211.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.10 : 1,420.65 = 807.90 : x
  2. Step 2: Convert to fraction form
    947.10/1,420.65 = 807.90/x
  3. Step 3: Cross multiply
    947.10x = 1,420.65 × 807.90
  4. Step 4: Simplify right side
    947.10x = 1,147,743.14
  5. Step 5: Solve for x
    x = 1,147,743.14/947.10
  6. Step 6: Final answer
    x = 1,211.85

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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.