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Finding the Fourth Proportional to 780.88, 1,078.12 and 486.58

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Solution

The fourth proportional to 780.88, 1,078.12 and 486.58 is: 671.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.88 : 1,078.12 = 486.58 : x
  2. Step 2: Convert to fraction form
    780.88/1,078.12 = 486.58/x
  3. Step 3: Cross multiply
    780.88x = 1,078.12 × 486.58
  4. Step 4: Simplify right side
    780.88x = 524,591.63
  5. Step 5: Solve for x
    x = 524,591.63/780.88
  6. Step 6: Final answer
    x = 671.80

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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.