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Finding the Fourth Proportional to 909.78, 1,255.50 and 516.80

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Solution

The fourth proportional to 909.78, 1,255.50 and 516.80 is: 713.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    909.78 : 1,255.50 = 516.80 : x
  2. Step 2: Convert to fraction form
    909.78/1,255.50 = 516.80/x
  3. Step 3: Cross multiply
    909.78x = 1,255.50 × 516.80
  4. Step 4: Simplify right side
    909.78x = 648,838.48
  5. Step 5: Solve for x
    x = 648,838.48/909.78
  6. Step 6: Final answer
    x = 713.18

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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.