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Finding the Fourth Proportional to 780.47, 1,076.35 and 515.15

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Solution

The fourth proportional to 780.47, 1,076.35 and 515.15 is: 710.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.47 : 1,076.35 = 515.15 : x
  2. Step 2: Convert to fraction form
    780.47/1,076.35 = 515.15/x
  3. Step 3: Cross multiply
    780.47x = 1,076.35 × 515.15
  4. Step 4: Simplify right side
    780.47x = 554,481.70
  5. Step 5: Solve for x
    x = 554,481.70/780.47
  6. Step 6: Final answer
    x = 710.45

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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.