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Finding the Fourth Proportional to 717.65, 990.36 and 407.15

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Solution

The fourth proportional to 717.65, 990.36 and 407.15 is: 561.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.65 : 990.36 = 407.15 : x
  2. Step 2: Convert to fraction form
    717.65/990.36 = 407.15/x
  3. Step 3: Cross multiply
    717.65x = 990.36 × 407.15
  4. Step 4: Simplify right side
    717.65x = 403,220.56
  5. Step 5: Solve for x
    x = 403,220.56/717.65
  6. Step 6: Final answer
    x = 561.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.