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Finding the Fourth Proportional to 661.68, 991.80 and 430.73

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Solution

The fourth proportional to 661.68, 991.80 and 430.73 is: 645.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.68 : 991.80 = 430.73 : x
  2. Step 2: Convert to fraction form
    661.68/991.80 = 430.73/x
  3. Step 3: Cross multiply
    661.68x = 991.80 × 430.73
  4. Step 4: Simplify right side
    661.68x = 427,198.01
  5. Step 5: Solve for x
    x = 427,198.01/661.68
  6. Step 6: Final answer
    x = 645.63

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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.