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Finding the Fourth Proportional to 491.70, 678.20 and 316.88

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Solution

The fourth proportional to 491.70, 678.20 and 316.88 is: 437.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.70 : 678.20 = 316.88 : x
  2. Step 2: Convert to fraction form
    491.70/678.20 = 316.88/x
  3. Step 3: Cross multiply
    491.70x = 678.20 × 316.88
  4. Step 4: Simplify right side
    491.70x = 214,903.04
  5. Step 5: Solve for x
    x = 214,903.04/491.70
  6. Step 6: Final answer
    x = 437.06

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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.