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Finding the Fourth Proportional to 873.78, 1,205.46 and 640.50

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Solution

The fourth proportional to 873.78, 1,205.46 and 640.50 is: 883.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    873.78 : 1,205.46 = 640.50 : x
  2. Step 2: Convert to fraction form
    873.78/1,205.46 = 640.50/x
  3. Step 3: Cross multiply
    873.78x = 1,205.46 × 640.50
  4. Step 4: Simplify right side
    873.78x = 772,097.13
  5. Step 5: Solve for x
    x = 772,097.13/873.78
  6. Step 6: Final answer
    x = 883.63

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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.