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Finding the Fourth Proportional to 661.92, 991.84 and 430.40

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Solution

The fourth proportional to 661.92, 991.84 and 430.40 is: 644.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.92 : 991.84 = 430.40 : x
  2. Step 2: Convert to fraction form
    661.92/991.84 = 430.40/x
  3. Step 3: Cross multiply
    661.92x = 991.84 × 430.40
  4. Step 4: Simplify right side
    661.92x = 426,887.94
  5. Step 5: Solve for x
    x = 426,887.94/661.92
  6. Step 6: Final answer
    x = 644.92

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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.