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Finding the Fourth Proportional to 2,115, 3,172.50 and 653.76

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Solution

The fourth proportional to 2,115, 3,172.50 and 653.76 is: 980.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,115 : 3,172.50 = 653.76 : x
  2. Step 2: Convert to fraction form
    2,115/3,172.50 = 653.76/x
  3. Step 3: Cross multiply
    2,115x = 3,172.50 × 653.76
  4. Step 4: Simplify right side
    2,115x = 2,074,053.60
  5. Step 5: Solve for x
    x = 2,074,053.60/2,115
  6. Step 6: Final answer
    x = 980.64

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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.