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Finding the Fourth Proportional to 660.98, 991.80 and 429.80

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Solution

The fourth proportional to 660.98, 991.80 and 429.80 is: 644.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.98 : 991.80 = 429.80 : x
  2. Step 2: Convert to fraction form
    660.98/991.80 = 429.80/x
  3. Step 3: Cross multiply
    660.98x = 991.80 × 429.80
  4. Step 4: Simplify right side
    660.98x = 426,275.64
  5. Step 5: Solve for x
    x = 426,275.64/660.98
  6. Step 6: Final answer
    x = 644.91

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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.