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Finding the Fourth Proportional to 623.69, 860.99 and 390.81

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Solution

The fourth proportional to 623.69, 860.99 and 390.81 is: 539.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    623.69 : 860.99 = 390.81 : x
  2. Step 2: Convert to fraction form
    623.69/860.99 = 390.81/x
  3. Step 3: Cross multiply
    623.69x = 860.99 × 390.81
  4. Step 4: Simplify right side
    623.69x = 336,483.50
  5. Step 5: Solve for x
    x = 336,483.50/623.69
  6. Step 6: Final answer
    x = 539.50

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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.