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Finding the Fourth Proportional to 928.11, 1,391.76 and 278.70

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Solution

The fourth proportional to 928.11, 1,391.76 and 278.70 is: 417.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.11 : 1,391.76 = 278.70 : x
  2. Step 2: Convert to fraction form
    928.11/1,391.76 = 278.70/x
  3. Step 3: Cross multiply
    928.11x = 1,391.76 × 278.70
  4. Step 4: Simplify right side
    928.11x = 387,883.51
  5. Step 5: Solve for x
    x = 387,883.51/928.11
  6. Step 6: Final answer
    x = 417.93

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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.