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Finding the Fourth Proportional to 788.20, 1,087.64 and 438.80

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Solution

The fourth proportional to 788.20, 1,087.64 and 438.80 is: 605.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    788.20 : 1,087.64 = 438.80 : x
  2. Step 2: Convert to fraction form
    788.20/1,087.64 = 438.80/x
  3. Step 3: Cross multiply
    788.20x = 1,087.64 × 438.80
  4. Step 4: Simplify right side
    788.20x = 477,256.43
  5. Step 5: Solve for x
    x = 477,256.43/788.20
  6. Step 6: Final answer
    x = 605.50

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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.