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Finding the Fourth Proportional to 720.71, 1,078.05 and 621.75

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Solution

The fourth proportional to 720.71, 1,078.05 and 621.75 is: 930.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    720.71 : 1,078.05 = 621.75 : x
  2. Step 2: Convert to fraction form
    720.71/1,078.05 = 621.75/x
  3. Step 3: Cross multiply
    720.71x = 1,078.05 × 621.75
  4. Step 4: Simplify right side
    720.71x = 670,277.59
  5. Step 5: Solve for x
    x = 670,277.59/720.71
  6. Step 6: Final answer
    x = 930.02

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.