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Finding the Fourth Proportional to 679.10, 1,019.10 and 386.60

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Solution

The fourth proportional to 679.10, 1,019.10 and 386.60 is: 580.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.10 : 1,019.10 = 386.60 : x
  2. Step 2: Convert to fraction form
    679.10/1,019.10 = 386.60/x
  3. Step 3: Cross multiply
    679.10x = 1,019.10 × 386.60
  4. Step 4: Simplify right side
    679.10x = 393,984.06
  5. Step 5: Solve for x
    x = 393,984.06/679.10
  6. Step 6: Final answer
    x = 580.16

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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.