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Finding the Fourth Proportional to 858.64, 1,288.68 and 688.72

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Solution

The fourth proportional to 858.64, 1,288.68 and 688.72 is: 1,033.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.64 : 1,288.68 = 688.72 : x
  2. Step 2: Convert to fraction form
    858.64/1,288.68 = 688.72/x
  3. Step 3: Cross multiply
    858.64x = 1,288.68 × 688.72
  4. Step 4: Simplify right side
    858.64x = 887,539.69
  5. Step 5: Solve for x
    x = 887,539.69/858.64
  6. Step 6: Final answer
    x = 1,033.66

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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.