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Finding the Fourth Proportional to 831.40, 1,246.30 and 646.20

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Solution

The fourth proportional to 831.40, 1,246.30 and 646.20 is: 968.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.40 : 1,246.30 = 646.20 : x
  2. Step 2: Convert to fraction form
    831.40/1,246.30 = 646.20/x
  3. Step 3: Cross multiply
    831.40x = 1,246.30 × 646.20
  4. Step 4: Simplify right side
    831.40x = 805,359.06
  5. Step 5: Solve for x
    x = 805,359.06/831.40
  6. Step 6: Final answer
    x = 968.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.