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Finding the Fourth Proportional to 620.78, 931.20 and 328.46

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Solution

The fourth proportional to 620.78, 931.20 and 328.46 is: 492.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.78 : 931.20 = 328.46 : x
  2. Step 2: Convert to fraction form
    620.78/931.20 = 328.46/x
  3. Step 3: Cross multiply
    620.78x = 931.20 × 328.46
  4. Step 4: Simplify right side
    620.78x = 305,861.95
  5. Step 5: Solve for x
    x = 305,861.95/620.78
  6. Step 6: Final answer
    x = 492.71

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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.