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Finding the Fourth Proportional to 678.95, 1,018.39 and 288.70

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Solution

The fourth proportional to 678.95, 1,018.39 and 288.70 is: 433.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.95 : 1,018.39 = 288.70 : x
  2. Step 2: Convert to fraction form
    678.95/1,018.39 = 288.70/x
  3. Step 3: Cross multiply
    678.95x = 1,018.39 × 288.70
  4. Step 4: Simplify right side
    678.95x = 294,009.19
  5. Step 5: Solve for x
    x = 294,009.19/678.95
  6. Step 6: Final answer
    x = 433.04

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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.