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Finding the Fourth Proportional to 661.41, 990.78 and 315.07

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Solution

The fourth proportional to 661.41, 990.78 and 315.07 is: 471.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.41 : 990.78 = 315.07 : x
  2. Step 2: Convert to fraction form
    661.41/990.78 = 315.07/x
  3. Step 3: Cross multiply
    661.41x = 990.78 × 315.07
  4. Step 4: Simplify right side
    661.41x = 312,165.05
  5. Step 5: Solve for x
    x = 312,165.05/661.41
  6. Step 6: Final answer
    x = 471.97

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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.