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Finding the Fourth Proportional to 1,078.60, 1,618 and 385.20

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Solution

The fourth proportional to 1,078.60, 1,618 and 385.20 is: 577.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.60 : 1,618 = 385.20 : x
  2. Step 2: Convert to fraction form
    1,078.60/1,618 = 385.20/x
  3. Step 3: Cross multiply
    1,078.60x = 1,618 × 385.20
  4. Step 4: Simplify right side
    1,078.60x = 623,253.60
  5. Step 5: Solve for x
    x = 623,253.60/1,078.60
  6. Step 6: Final answer
    x = 577.84

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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.