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Finding the Fourth Proportional to 686.99, 947.66 and 421.56

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Solution

The fourth proportional to 686.99, 947.66 and 421.56 is: 581.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.99 : 947.66 = 421.56 : x
  2. Step 2: Convert to fraction form
    686.99/947.66 = 421.56/x
  3. Step 3: Cross multiply
    686.99x = 947.66 × 421.56
  4. Step 4: Simplify right side
    686.99x = 399,495.55
  5. Step 5: Solve for x
    x = 399,495.55/686.99
  6. Step 6: Final answer
    x = 581.52

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.