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Finding the Fourth Proportional to 715.20, 986.92 and 420.43

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Solution

The fourth proportional to 715.20, 986.92 and 420.43 is: 580.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.20 : 986.92 = 420.43 : x
  2. Step 2: Convert to fraction form
    715.20/986.92 = 420.43/x
  3. Step 3: Cross multiply
    715.20x = 986.92 × 420.43
  4. Step 4: Simplify right side
    715.20x = 414,930.78
  5. Step 5: Solve for x
    x = 414,930.78/715.20
  6. Step 6: Final answer
    x = 580.16

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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.