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Finding the Fourth Proportional to 862.20, 1,287.29 and 707.72

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Solution

The fourth proportional to 862.20, 1,287.29 and 707.72 is: 1,056.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    862.20 : 1,287.29 = 707.72 : x
  2. Step 2: Convert to fraction form
    862.20/1,287.29 = 707.72/x
  3. Step 3: Cross multiply
    862.20x = 1,287.29 × 707.72
  4. Step 4: Simplify right side
    862.20x = 911,036.21
  5. Step 5: Solve for x
    x = 911,036.21/862.20
  6. Step 6: Final answer
    x = 1,056.64

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.