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Finding the Fourth Proportional to 528.28, 728.21 and 388.55

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Solution

The fourth proportional to 528.28, 728.21 and 388.55 is: 535.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    528.28 : 728.21 = 388.55 : x
  2. Step 2: Convert to fraction form
    528.28/728.21 = 388.55/x
  3. Step 3: Cross multiply
    528.28x = 728.21 × 388.55
  4. Step 4: Simplify right side
    528.28x = 282,946.60
  5. Step 5: Solve for x
    x = 282,946.60/528.28
  6. Step 6: Final answer
    x = 535.60

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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.