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Finding the Fourth Proportional to 912.86, 1,258.15 and 660.78

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Solution

The fourth proportional to 912.86, 1,258.15 and 660.78 is: 910.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.86 : 1,258.15 = 660.78 : x
  2. Step 2: Convert to fraction form
    912.86/1,258.15 = 660.78/x
  3. Step 3: Cross multiply
    912.86x = 1,258.15 × 660.78
  4. Step 4: Simplify right side
    912.86x = 831,360.36
  5. Step 5: Solve for x
    x = 831,360.36/912.86
  6. Step 6: Final answer
    x = 910.72

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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.