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Finding the Fourth Proportional to 910.80, 1,257.72 and 770.80

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Solution

The fourth proportional to 910.80, 1,257.72 and 770.80 is: 1,064.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    910.80 : 1,257.72 = 770.80 : x
  2. Step 2: Convert to fraction form
    910.80/1,257.72 = 770.80/x
  3. Step 3: Cross multiply
    910.80x = 1,257.72 × 770.80
  4. Step 4: Simplify right side
    910.80x = 969,450.58
  5. Step 5: Solve for x
    x = 969,450.58/910.80
  6. Step 6: Final answer
    x = 1,064.39

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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.