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Finding the Fourth Proportional to 660.68, 990.60 and 429.28

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Solution

The fourth proportional to 660.68, 990.60 and 429.28 is: 643.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.68 : 990.60 = 429.28 : x
  2. Step 2: Convert to fraction form
    660.68/990.60 = 429.28/x
  3. Step 3: Cross multiply
    660.68x = 990.60 × 429.28
  4. Step 4: Simplify right side
    660.68x = 425,244.77
  5. Step 5: Solve for x
    x = 425,244.77/660.68
  6. Step 6: Final answer
    x = 643.65

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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.