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Finding the Fourth Proportional to 1,256.48, 1,885.20 and 640.60

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Solution

The fourth proportional to 1,256.48, 1,885.20 and 640.60 is: 961.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,256.48 : 1,885.20 = 640.60 : x
  2. Step 2: Convert to fraction form
    1,256.48/1,885.20 = 640.60/x
  3. Step 3: Cross multiply
    1,256.48x = 1,885.20 × 640.60
  4. Step 4: Simplify right side
    1,256.48x = 1,207,659.12
  5. Step 5: Solve for x
    x = 1,207,659.12/1,256.48
  6. Step 6: Final answer
    x = 961.14

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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.