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Finding the Fourth Proportional to 947.50, 1,420.86 and 399.40

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Solution

The fourth proportional to 947.50, 1,420.86 and 399.40 is: 598.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    947.50 : 1,420.86 = 399.40 : x
  2. Step 2: Convert to fraction form
    947.50/1,420.86 = 399.40/x
  3. Step 3: Cross multiply
    947.50x = 1,420.86 × 399.40
  4. Step 4: Simplify right side
    947.50x = 567,491.48
  5. Step 5: Solve for x
    x = 567,491.48/947.50
  6. Step 6: Final answer
    x = 598.94

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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.