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Finding the Fourth Proportional to 678.20, 918.45 and 678.20

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Solution

The fourth proportional to 678.20, 918.45 and 678.20 is: 918.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.20 : 918.45 = 678.20 : x
  2. Step 2: Convert to fraction form
    678.20/918.45 = 678.20/x
  3. Step 3: Cross multiply
    678.20x = 918.45 × 678.20
  4. Step 4: Simplify right side
    678.20x = 622,892.79
  5. Step 5: Solve for x
    x = 622,892.79/678.20
  6. Step 6: Final answer
    x = 918.45

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1.5x scale

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.