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Finding the Fourth Proportional to 947.20, 1,421.15 and 427.05

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Solution

The fourth proportional to 947.20, 1,421.15 and 427.05 is: 640.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.20 : 1,421.15 = 427.05 : x
  2. Step 2: Convert to fraction form
    947.20/1,421.15 = 427.05/x
  3. Step 3: Cross multiply
    947.20x = 1,421.15 × 427.05
  4. Step 4: Simplify right side
    947.20x = 606,896.07
  5. Step 5: Solve for x
    x = 606,896.07/947.20
  6. Step 6: Final answer
    x = 640.73

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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.