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Finding the Fourth Proportional to 831.58, 1,140.75 and 781.90

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Solution

The fourth proportional to 831.58, 1,140.75 and 781.90 is: 1,072.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.58 : 1,140.75 = 781.90 : x
  2. Step 2: Convert to fraction form
    831.58/1,140.75 = 781.90/x
  3. Step 3: Cross multiply
    831.58x = 1,140.75 × 781.90
  4. Step 4: Simplify right side
    831.58x = 891,952.43
  5. Step 5: Solve for x
    x = 891,952.43/831.58
  6. Step 6: Final answer
    x = 1,072.60

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.