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Finding the Fourth Proportional to 678.80, 917.10 and 678.80

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Solution

The fourth proportional to 678.80, 917.10 and 678.80 is: 917.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.80 : 917.10 = 678.80 : x
  2. Step 2: Convert to fraction form
    678.80/917.10 = 678.80/x
  3. Step 3: Cross multiply
    678.80x = 917.10 × 678.80
  4. Step 4: Simplify right side
    678.80x = 622,527.48
  5. Step 5: Solve for x
    x = 622,527.48/678.80
  6. Step 6: Final answer
    x = 917.10

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Why These Related Problems?

These problems maintain the same ratio (1.35) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.