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Finding the Fourth Proportional to 918.10, 1,376.88 and 431.56

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Solution

The fourth proportional to 918.10, 1,376.88 and 431.56 is: 647.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.10 : 1,376.88 = 431.56 : x
  2. Step 2: Convert to fraction form
    918.10/1,376.88 = 431.56/x
  3. Step 3: Cross multiply
    918.10x = 1,376.88 × 431.56
  4. Step 4: Simplify right side
    918.10x = 594,206.33
  5. Step 5: Solve for x
    x = 594,206.33/918.10
  6. Step 6: Final answer
    x = 647.21

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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.