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Finding the Fourth Proportional to 661.65, 991.99 and 314.91

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Solution

The fourth proportional to 661.65, 991.99 and 314.91 is: 472.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.65 : 991.99 = 314.91 : x
  2. Step 2: Convert to fraction form
    661.65/991.99 = 314.91/x
  3. Step 3: Cross multiply
    661.65x = 991.99 × 314.91
  4. Step 4: Simplify right side
    661.65x = 312,387.57
  5. Step 5: Solve for x
    x = 312,387.57/661.65
  6. Step 6: Final answer
    x = 472.13

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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.