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Finding the Fourth Proportional to 491.63, 678.86 and 317.28

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Solution

The fourth proportional to 491.63, 678.86 and 317.28 is: 438.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.63 : 678.86 = 317.28 : x
  2. Step 2: Convert to fraction form
    491.63/678.86 = 317.28/x
  3. Step 3: Cross multiply
    491.63x = 678.86 × 317.28
  4. Step 4: Simplify right side
    491.63x = 215,387.11
  5. Step 5: Solve for x
    x = 215,387.11/491.63
  6. Step 6: Final answer
    x = 438.11

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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.