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Finding the Fourth Proportional to 491.64, 678.48 and 305.15

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Solution

The fourth proportional to 491.64, 678.48 and 305.15 is: 421.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.64 : 678.48 = 305.15 : x
  2. Step 2: Convert to fraction form
    491.64/678.48 = 305.15/x
  3. Step 3: Cross multiply
    491.64x = 678.48 × 305.15
  4. Step 4: Simplify right side
    491.64x = 207,034.78
  5. Step 5: Solve for x
    x = 207,034.78/491.64
  6. Step 6: Final answer
    x = 421.11

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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.