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Finding the Fourth Proportional to 780.22, 1,075.89 and 640.54

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Solution

The fourth proportional to 780.22, 1,075.89 and 640.54 is: 883.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.22 : 1,075.89 = 640.54 : x
  2. Step 2: Convert to fraction form
    780.22/1,075.89 = 640.54/x
  3. Step 3: Cross multiply
    780.22x = 1,075.89 × 640.54
  4. Step 4: Simplify right side
    780.22x = 689,150.58
  5. Step 5: Solve for x
    x = 689,150.58/780.22
  6. Step 6: Final answer
    x = 883.28

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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.