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Finding the Fourth Proportional to 781.65, 1,078.11 and 585.63

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Solution

The fourth proportional to 781.65, 1,078.11 and 585.63 is: 807.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.65 : 1,078.11 = 585.63 : x
  2. Step 2: Convert to fraction form
    781.65/1,078.11 = 585.63/x
  3. Step 3: Cross multiply
    781.65x = 1,078.11 × 585.63
  4. Step 4: Simplify right side
    781.65x = 631,373.56
  5. Step 5: Solve for x
    x = 631,373.56/781.65
  6. Step 6: Final answer
    x = 807.74

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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.