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Finding the Fourth Proportional to 679, 1,019.86 and 405.63

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Solution

The fourth proportional to 679, 1,019.86 and 405.63 is: 609.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    679 : 1,019.86 = 405.63 : x
  2. Step 2: Convert to fraction form
    679/1,019.86 = 405.63/x
  3. Step 3: Cross multiply
    679x = 1,019.86 × 405.63
  4. Step 4: Simplify right side
    679x = 413,685.81
  5. Step 5: Solve for x
    x = 413,685.81/679
  6. Step 6: Final answer
    x = 609.26

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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.