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Finding the Fourth Proportional to 491.61, 678.63 and 305.31

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Solution

The fourth proportional to 491.61, 678.63 and 305.31 is: 421.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.61 : 678.63 = 305.31 : x
  2. Step 2: Convert to fraction form
    491.61/678.63 = 305.31/x
  3. Step 3: Cross multiply
    491.61x = 678.63 × 305.31
  4. Step 4: Simplify right side
    491.61x = 207,196.22
  5. Step 5: Solve for x
    x = 207,196.22/491.61
  6. Step 6: Final answer
    x = 421.46

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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.