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Finding the Fourth Proportional to 780.75, 1,077.65 and 515.38

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Solution

The fourth proportional to 780.75, 1,077.65 and 515.38 is: 711.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.75 : 1,077.65 = 515.38 : x
  2. Step 2: Convert to fraction form
    780.75/1,077.65 = 515.38/x
  3. Step 3: Cross multiply
    780.75x = 1,077.65 × 515.38
  4. Step 4: Simplify right side
    780.75x = 555,400.55
  5. Step 5: Solve for x
    x = 555,400.55/780.75
  6. Step 6: Final answer
    x = 711.37

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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.