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Finding the Fourth Proportional to 1,225.29, 1,690.85 and 665.75

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Solution

The fourth proportional to 1,225.29, 1,690.85 and 665.75 is: 918.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,225.29 : 1,690.85 = 665.75 : x
  2. Step 2: Convert to fraction form
    1,225.29/1,690.85 = 665.75/x
  3. Step 3: Cross multiply
    1,225.29x = 1,690.85 × 665.75
  4. Step 4: Simplify right side
    1,225.29x = 1,125,689.28
  5. Step 5: Solve for x
    x = 1,125,689.28/1,225.29
  6. Step 6: Final answer
    x = 918.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.