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Finding the Fourth Proportional to 661.68, 991.28 and 418.24

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Solution

The fourth proportional to 661.68, 991.28 and 418.24 is: 626.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.68 : 991.28 = 418.24 : x
  2. Step 2: Convert to fraction form
    661.68/991.28 = 418.24/x
  3. Step 3: Cross multiply
    661.68x = 991.28 × 418.24
  4. Step 4: Simplify right side
    661.68x = 414,592.95
  5. Step 5: Solve for x
    x = 414,592.95/661.68
  6. Step 6: Final answer
    x = 626.58

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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.