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Finding the Fourth Proportional to 789.39, 1,089.95 and 509.79

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Solution

The fourth proportional to 789.39, 1,089.95 and 509.79 is: 703.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    789.39 : 1,089.95 = 509.79 : x
  2. Step 2: Convert to fraction form
    789.39/1,089.95 = 509.79/x
  3. Step 3: Cross multiply
    789.39x = 1,089.95 × 509.79
  4. Step 4: Simplify right side
    789.39x = 555,643.06
  5. Step 5: Solve for x
    x = 555,643.06/789.39
  6. Step 6: Final answer
    x = 703.89

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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.