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Finding the Fourth Proportional to 921.40, 1,381.96 and 305

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Solution

The fourth proportional to 921.40, 1,381.96 and 305 is: 457.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.40 : 1,381.96 = 305 : x
  2. Step 2: Convert to fraction form
    921.40/1,381.96 = 305/x
  3. Step 3: Cross multiply
    921.40x = 1,381.96 × 305
  4. Step 4: Simplify right side
    921.40x = 421,497.80
  5. Step 5: Solve for x
    x = 421,497.80/921.40
  6. Step 6: Final answer
    x = 457.45

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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.