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Finding the Fourth Proportional to 620.53, 856.91 and 399.87

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Solution

The fourth proportional to 620.53, 856.91 and 399.87 is: 552.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.53 : 856.91 = 399.87 : x
  2. Step 2: Convert to fraction form
    620.53/856.91 = 399.87/x
  3. Step 3: Cross multiply
    620.53x = 856.91 × 399.87
  4. Step 4: Simplify right side
    620.53x = 342,652.60
  5. Step 5: Solve for x
    x = 342,652.60/620.53
  6. Step 6: Final answer
    x = 552.19

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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.