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Finding the Fourth Proportional to 491.76, 678.28 and 305.05

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Solution

The fourth proportional to 491.76, 678.28 and 305.05 is: 420.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.76 : 678.28 = 305.05 : x
  2. Step 2: Convert to fraction form
    491.76/678.28 = 305.05/x
  3. Step 3: Cross multiply
    491.76x = 678.28 × 305.05
  4. Step 4: Simplify right side
    491.76x = 206,909.31
  5. Step 5: Solve for x
    x = 206,909.31/491.76
  6. Step 6: Final answer
    x = 420.75

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.