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Finding the Fourth Proportional to 799.40, 1,100.78 and 781.20

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Solution

The fourth proportional to 799.40, 1,100.78 and 781.20 is: 1,075.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    799.40 : 1,100.78 = 781.20 : x
  2. Step 2: Convert to fraction form
    799.40/1,100.78 = 781.20/x
  3. Step 3: Cross multiply
    799.40x = 1,100.78 × 781.20
  4. Step 4: Simplify right side
    799.40x = 859,925.43
  5. Step 5: Solve for x
    x = 859,925.43/799.40
  6. Step 6: Final answer
    x = 1,075.72

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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.