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Finding the Fourth Proportional to 420.18, 580.40 and 321.76

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Solution

The fourth proportional to 420.18, 580.40 and 321.76 is: 444.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.18 : 580.40 = 321.76 : x
  2. Step 2: Convert to fraction form
    420.18/580.40 = 321.76/x
  3. Step 3: Cross multiply
    420.18x = 580.40 × 321.76
  4. Step 4: Simplify right side
    420.18x = 186,749.50
  5. Step 5: Solve for x
    x = 186,749.50/420.18
  6. Step 6: Final answer
    x = 444.45

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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.