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Finding the Fourth Proportional to 872.40, 1,307.40 and 769.20

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Solution

The fourth proportional to 872.40, 1,307.40 and 769.20 is: 1,152.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    872.40 : 1,307.40 = 769.20 : x
  2. Step 2: Convert to fraction form
    872.40/1,307.40 = 769.20/x
  3. Step 3: Cross multiply
    872.40x = 1,307.40 × 769.20
  4. Step 4: Simplify right side
    872.40x = 1,005,652.08
  5. Step 5: Solve for x
    x = 1,005,652.08/872.40
  6. Step 6: Final answer
    x = 1,152.74

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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.