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Finding the Fourth Proportional to 780.01, 1,076.85 and 515.21

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Solution

The fourth proportional to 780.01, 1,076.85 and 515.21 is: 711.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.01 : 1,076.85 = 515.21 : x
  2. Step 2: Convert to fraction form
    780.01/1,076.85 = 515.21/x
  3. Step 3: Cross multiply
    780.01x = 1,076.85 × 515.21
  4. Step 4: Simplify right side
    780.01x = 554,803.89
  5. Step 5: Solve for x
    x = 554,803.89/780.01
  6. Step 6: Final answer
    x = 711.28

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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.