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Finding the Fourth Proportional to 719.90, 993.42 and 405.15

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Solution

The fourth proportional to 719.90, 993.42 and 405.15 is: 559.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    719.90 : 993.42 = 405.15 : x
  2. Step 2: Convert to fraction form
    719.90/993.42 = 405.15/x
  3. Step 3: Cross multiply
    719.90x = 993.42 × 405.15
  4. Step 4: Simplify right side
    719.90x = 402,484.11
  5. Step 5: Solve for x
    x = 402,484.11/719.90
  6. Step 6: Final answer
    x = 559.09

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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.