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Finding the Fourth Proportional to 620.60, 856.56 and 485.74

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Solution

The fourth proportional to 620.60, 856.56 and 485.74 is: 670.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.60 : 856.56 = 485.74 : x
  2. Step 2: Convert to fraction form
    620.60/856.56 = 485.74/x
  3. Step 3: Cross multiply
    620.60x = 856.56 × 485.74
  4. Step 4: Simplify right side
    620.60x = 416,062.10
  5. Step 5: Solve for x
    x = 416,062.10/620.60
  6. Step 6: Final answer
    x = 670.42

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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.