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Finding the Fourth Proportional to 1,087, 1,631.74 and 438.20

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Solution

The fourth proportional to 1,087, 1,631.74 and 438.20 is: 657.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,087 : 1,631.74 = 438.20 : x
  2. Step 2: Convert to fraction form
    1,087/1,631.74 = 438.20/x
  3. Step 3: Cross multiply
    1,087x = 1,631.74 × 438.20
  4. Step 4: Simplify right side
    1,087x = 715,028.47
  5. Step 5: Solve for x
    x = 715,028.47/1,087
  6. Step 6: Final answer
    x = 657.80

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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.