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Finding the Fourth Proportional to 491.91, 678.71 and 387.01

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Solution

The fourth proportional to 491.91, 678.71 and 387.01 is: 533.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.91 : 678.71 = 387.01 : x
  2. Step 2: Convert to fraction form
    491.91/678.71 = 387.01/x
  3. Step 3: Cross multiply
    491.91x = 678.71 × 387.01
  4. Step 4: Simplify right side
    491.91x = 262,669.37
  5. Step 5: Solve for x
    x = 262,669.37/491.91
  6. Step 6: Final answer
    x = 533.98

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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.