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Finding the Fourth Proportional to 620.78, 856.31 and 384.66

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Solution

The fourth proportional to 620.78, 856.31 and 384.66 is: 530.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.78 : 856.31 = 384.66 : x
  2. Step 2: Convert to fraction form
    620.78/856.31 = 384.66/x
  3. Step 3: Cross multiply
    620.78x = 856.31 × 384.66
  4. Step 4: Simplify right side
    620.78x = 329,386.28
  5. Step 5: Solve for x
    x = 329,386.28/620.78
  6. Step 6: Final answer
    x = 530.60

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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.