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Finding the Fourth Proportional to 1,139.94, 1,573.08 and 642.60

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Solution

The fourth proportional to 1,139.94, 1,573.08 and 642.60 is: 886.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,139.94 : 1,573.08 = 642.60 : x
  2. Step 2: Convert to fraction form
    1,139.94/1,573.08 = 642.60/x
  3. Step 3: Cross multiply
    1,139.94x = 1,573.08 × 642.60
  4. Step 4: Simplify right side
    1,139.94x = 1,010,861.21
  5. Step 5: Solve for x
    x = 1,010,861.21/1,139.94
  6. Step 6: Final answer
    x = 886.77

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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.