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Finding the Fourth Proportional to 1,038.78, 1,558.18 and 258.78

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Solution

The fourth proportional to 1,038.78, 1,558.18 and 258.78 is: 388.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,038.78 : 1,558.18 = 258.78 : x
  2. Step 2: Convert to fraction form
    1,038.78/1,558.18 = 258.78/x
  3. Step 3: Cross multiply
    1,038.78x = 1,558.18 × 258.78
  4. Step 4: Simplify right side
    1,038.78x = 403,232.48
  5. Step 5: Solve for x
    x = 403,232.48/1,038.78
  6. Step 6: Final answer
    x = 388.18

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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.