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Finding the Fourth Proportional to 913.91, 1,261.65 and 620.72

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Solution

The fourth proportional to 913.91, 1,261.65 and 620.72 is: 856.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    913.91 : 1,261.65 = 620.72 : x
  2. Step 2: Convert to fraction form
    913.91/1,261.65 = 620.72/x
  3. Step 3: Cross multiply
    913.91x = 1,261.65 × 620.72
  4. Step 4: Simplify right side
    913.91x = 783,125.08
  5. Step 5: Solve for x
    x = 783,125.08/913.91
  6. Step 6: Final answer
    x = 856.90

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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.