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Finding the Fourth Proportional to 691.20, 998.40 and 691.20

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Solution

The fourth proportional to 691.20, 998.40 and 691.20 is: 998.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.20 : 998.40 = 691.20 : x
  2. Step 2: Convert to fraction form
    691.20/998.40 = 691.20/x
  3. Step 3: Cross multiply
    691.20x = 998.40 × 691.20
  4. Step 4: Simplify right side
    691.20x = 690,094.08
  5. Step 5: Solve for x
    x = 690,094.08/691.20
  6. Step 6: Final answer
    x = 998.40

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.44) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.