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Finding the Fourth Proportional to 420.86, 580.57 and 289.64

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Solution

The fourth proportional to 420.86, 580.57 and 289.64 is: 399.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.86 : 580.57 = 289.64 : x
  2. Step 2: Convert to fraction form
    420.86/580.57 = 289.64/x
  3. Step 3: Cross multiply
    420.86x = 580.57 × 289.64
  4. Step 4: Simplify right side
    420.86x = 168,157.02
  5. Step 5: Solve for x
    x = 168,157.02/420.86
  6. Step 6: Final answer
    x = 399.55

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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.