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Finding the Fourth Proportional to 779.40, 1,070.78 and 631.59

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Solution

The fourth proportional to 779.40, 1,070.78 and 631.59 is: 867.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    779.40 : 1,070.78 = 631.59 : x
  2. Step 2: Convert to fraction form
    779.40/1,070.78 = 631.59/x
  3. Step 3: Cross multiply
    779.40x = 1,070.78 × 631.59
  4. Step 4: Simplify right side
    779.40x = 676,290.78
  5. Step 5: Solve for x
    x = 676,290.78/779.40
  6. Step 6: Final answer
    x = 867.71

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.