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Finding the Fourth Proportional to 689.64, 1,032 and 678.72

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Solution

The fourth proportional to 689.64, 1,032 and 678.72 is: 1,015.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.64 : 1,032 = 678.72 : x
  2. Step 2: Convert to fraction form
    689.64/1,032 = 678.72/x
  3. Step 3: Cross multiply
    689.64x = 1,032 × 678.72
  4. Step 4: Simplify right side
    689.64x = 700,439.04
  5. Step 5: Solve for x
    x = 700,439.04/689.64
  6. Step 6: Final answer
    x = 1,015.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.