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Finding the Fourth Proportional to 781.59, 1,075.85 and 707.78

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Solution

The fourth proportional to 781.59, 1,075.85 and 707.78 is: 974.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.59 : 1,075.85 = 707.78 : x
  2. Step 2: Convert to fraction form
    781.59/1,075.85 = 707.78/x
  3. Step 3: Cross multiply
    781.59x = 1,075.85 × 707.78
  4. Step 4: Simplify right side
    781.59x = 761,469.57
  5. Step 5: Solve for x
    x = 761,469.57/781.59
  6. Step 6: Final answer
    x = 974.26

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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.