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Finding the Fourth Proportional to 620.02, 855.65 and 399.40

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Solution

The fourth proportional to 620.02, 855.65 and 399.40 is: 551.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.02 : 855.65 = 399.40 : x
  2. Step 2: Convert to fraction form
    620.02/855.65 = 399.40/x
  3. Step 3: Cross multiply
    620.02x = 855.65 × 399.40
  4. Step 4: Simplify right side
    620.02x = 341,746.61
  5. Step 5: Solve for x
    x = 341,746.61/620.02
  6. Step 6: Final answer
    x = 551.19

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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.