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Finding the Fourth Proportional to 1,225.19, 1,690.77 and 665.66

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Solution

The fourth proportional to 1,225.19, 1,690.77 and 665.66 is: 918.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,225.19 : 1,690.77 = 665.66 : x
  2. Step 2: Convert to fraction form
    1,225.19/1,690.77 = 665.66/x
  3. Step 3: Cross multiply
    1,225.19x = 1,690.77 × 665.66
  4. Step 4: Simplify right side
    1,225.19x = 1,125,477.96
  5. Step 5: Solve for x
    x = 1,125,477.96/1,225.19
  6. Step 6: Final answer
    x = 918.62

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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.