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Finding the Fourth Proportional to 900.78, 1,351.26 and 315.72

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Solution

The fourth proportional to 900.78, 1,351.26 and 315.72 is: 473.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    900.78 : 1,351.26 = 315.72 : x
  2. Step 2: Convert to fraction form
    900.78/1,351.26 = 315.72/x
  3. Step 3: Cross multiply
    900.78x = 1,351.26 × 315.72
  4. Step 4: Simplify right side
    900.78x = 426,619.81
  5. Step 5: Solve for x
    x = 426,619.81/900.78
  6. Step 6: Final answer
    x = 473.61

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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.