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Finding the Fourth Proportional to 491.80, 678.40 and 295.20

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Solution

The fourth proportional to 491.80, 678.40 and 295.20 is: 407.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.80 : 678.40 = 295.20 : x
  2. Step 2: Convert to fraction form
    491.80/678.40 = 295.20/x
  3. Step 3: Cross multiply
    491.80x = 678.40 × 295.20
  4. Step 4: Simplify right side
    491.80x = 200,263.68
  5. Step 5: Solve for x
    x = 200,263.68/491.80
  6. Step 6: Final answer
    x = 407.21

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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.