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Finding the Fourth Proportional to 620, 855.64 and 387.28

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Solution

The fourth proportional to 620, 855.64 and 387.28 is: 534.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    620 : 855.64 = 387.28 : x
  2. Step 2: Convert to fraction form
    620/855.64 = 387.28/x
  3. Step 3: Cross multiply
    620x = 855.64 × 387.28
  4. Step 4: Simplify right side
    620x = 331,372.26
  5. Step 5: Solve for x
    x = 331,372.26/620
  6. Step 6: Final answer
    x = 534.47

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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.