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Finding the Fourth Proportional to 491.87, 678.66 and 312.35

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Solution

The fourth proportional to 491.87, 678.66 and 312.35 is: 430.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.87 : 678.66 = 312.35 : x
  2. Step 2: Convert to fraction form
    491.87/678.66 = 312.35/x
  3. Step 3: Cross multiply
    491.87x = 678.66 × 312.35
  4. Step 4: Simplify right side
    491.87x = 211,981.15
  5. Step 5: Solve for x
    x = 211,981.15/491.87
  6. Step 6: Final answer
    x = 430.97

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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.