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Finding the Fourth Proportional to 780.89, 1,078.99 and 624.80

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Solution

The fourth proportional to 780.89, 1,078.99 and 624.80 is: 863.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.89 : 1,078.99 = 624.80 : x
  2. Step 2: Convert to fraction form
    780.89/1,078.99 = 624.80/x
  3. Step 3: Cross multiply
    780.89x = 1,078.99 × 624.80
  4. Step 4: Simplify right side
    780.89x = 674,154.09
  5. Step 5: Solve for x
    x = 674,154.09/780.89
  6. Step 6: Final answer
    x = 863.32

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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.