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Finding the Fourth Proportional to 928.67, 1,279.87 and 870.21

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Solution

The fourth proportional to 928.67, 1,279.87 and 870.21 is: 1,199.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.67 : 1,279.87 = 870.21 : x
  2. Step 2: Convert to fraction form
    928.67/1,279.87 = 870.21/x
  3. Step 3: Cross multiply
    928.67x = 1,279.87 × 870.21
  4. Step 4: Simplify right side
    928.67x = 1,113,753.50
  5. Step 5: Solve for x
    x = 1,113,753.50/928.67
  6. Step 6: Final answer
    x = 1,199.31

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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.