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Finding the Fourth Proportional to 661.27, 990.43 and 648.57

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Solution

The fourth proportional to 661.27, 990.43 and 648.57 is: 971.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.27 : 990.43 = 648.57 : x
  2. Step 2: Convert to fraction form
    661.27/990.43 = 648.57/x
  3. Step 3: Cross multiply
    661.27x = 990.43 × 648.57
  4. Step 4: Simplify right side
    661.27x = 642,359.94
  5. Step 5: Solve for x
    x = 642,359.94/661.27
  6. Step 6: Final answer
    x = 971.40

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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.