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Finding the Fourth Proportional to 628.40, 940.86 and 409.28

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Solution

The fourth proportional to 628.40, 940.86 and 409.28 is: 612.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    628.40 : 940.86 = 409.28 : x
  2. Step 2: Convert to fraction form
    628.40/940.86 = 409.28/x
  3. Step 3: Cross multiply
    628.40x = 940.86 × 409.28
  4. Step 4: Simplify right side
    628.40x = 385,075.18
  5. Step 5: Solve for x
    x = 385,075.18/628.40
  6. Step 6: Final answer
    x = 612.79

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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.