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Finding the Fourth Proportional to 661.32, 990.72 and 387.54

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Solution

The fourth proportional to 661.32, 990.72 and 387.54 is: 580.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.32 : 990.72 = 387.54 : x
  2. Step 2: Convert to fraction form
    661.32/990.72 = 387.54/x
  3. Step 3: Cross multiply
    661.32x = 990.72 × 387.54
  4. Step 4: Simplify right side
    661.32x = 383,943.63
  5. Step 5: Solve for x
    x = 383,943.63/661.32
  6. Step 6: Final answer
    x = 580.57

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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.