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Finding the Fourth Proportional to 661.20, 990.72 and 417.84

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Solution

The fourth proportional to 661.20, 990.72 and 417.84 is: 626.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 990.72 = 417.84 : x
  2. Step 2: Convert to fraction form
    661.20/990.72 = 417.84/x
  3. Step 3: Cross multiply
    661.20x = 990.72 × 417.84
  4. Step 4: Simplify right side
    661.20x = 413,962.44
  5. Step 5: Solve for x
    x = 413,962.44/661.20
  6. Step 6: Final answer
    x = 626.08

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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.