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Finding the Fourth Proportional to 491.36, 678.30 and 386.20

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Solution

The fourth proportional to 491.36, 678.30 and 386.20 is: 533.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.36 : 678.30 = 386.20 : x
  2. Step 2: Convert to fraction form
    491.36/678.30 = 386.20/x
  3. Step 3: Cross multiply
    491.36x = 678.30 × 386.20
  4. Step 4: Simplify right side
    491.36x = 261,959.46
  5. Step 5: Solve for x
    x = 261,959.46/491.36
  6. Step 6: Final answer
    x = 533.13

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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.