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Finding the Fourth Proportional to 623.28, 860.40 and 390.72

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Solution

The fourth proportional to 623.28, 860.40 and 390.72 is: 539.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    623.28 : 860.40 = 390.72 : x
  2. Step 2: Convert to fraction form
    623.28/860.40 = 390.72/x
  3. Step 3: Cross multiply
    623.28x = 860.40 × 390.72
  4. Step 4: Simplify right side
    623.28x = 336,175.49
  5. Step 5: Solve for x
    x = 336,175.49/623.28
  6. Step 6: Final answer
    x = 539.37

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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.