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Finding the Fourth Proportional to 1,018.32, 1,405.28 and 645.51

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Solution

The fourth proportional to 1,018.32, 1,405.28 and 645.51 is: 890.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,018.32 : 1,405.28 = 645.51 : x
  2. Step 2: Convert to fraction form
    1,018.32/1,405.28 = 645.51/x
  3. Step 3: Cross multiply
    1,018.32x = 1,405.28 × 645.51
  4. Step 4: Simplify right side
    1,018.32x = 907,129.18
  5. Step 5: Solve for x
    x = 907,129.18/1,018.32
  6. Step 6: Final answer
    x = 890.81

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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.