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Finding the Fourth Proportional to 839.40, 1,155.62 and 780.52

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Solution

The fourth proportional to 839.40, 1,155.62 and 780.52 is: 1,074.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    839.40 : 1,155.62 = 780.52 : x
  2. Step 2: Convert to fraction form
    839.40/1,155.62 = 780.52/x
  3. Step 3: Cross multiply
    839.40x = 1,155.62 × 780.52
  4. Step 4: Simplify right side
    839.40x = 901,984.52
  5. Step 5: Solve for x
    x = 901,984.52/839.40
  6. Step 6: Final answer
    x = 1,074.56

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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.