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Finding the Fourth Proportional to 780.26, 1,076.57 and 485.37

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Solution

The fourth proportional to 780.26, 1,076.57 and 485.37 is: 669.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.26 : 1,076.57 = 485.37 : x
  2. Step 2: Convert to fraction form
    780.26/1,076.57 = 485.37/x
  3. Step 3: Cross multiply
    780.26x = 1,076.57 × 485.37
  4. Step 4: Simplify right side
    780.26x = 522,536.90
  5. Step 5: Solve for x
    x = 522,536.90/780.26
  6. Step 6: Final answer
    x = 669.70

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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.