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Finding the Fourth Proportional to 918.70, 1,378.05 and 554.20

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Solution

The fourth proportional to 918.70, 1,378.05 and 554.20 is: 831.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.70 : 1,378.05 = 554.20 : x
  2. Step 2: Convert to fraction form
    918.70/1,378.05 = 554.20/x
  3. Step 3: Cross multiply
    918.70x = 1,378.05 × 554.20
  4. Step 4: Simplify right side
    918.70x = 763,715.31
  5. Step 5: Solve for x
    x = 763,715.31/918.70
  6. Step 6: Final answer
    x = 831.30

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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.