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Finding the Fourth Proportional to 1,230, 1,698.48 and 921.12

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Solution

The fourth proportional to 1,230, 1,698.48 and 921.12 is: 1,271.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,230 : 1,698.48 = 921.12 : x
  2. Step 2: Convert to fraction form
    1,230/1,698.48 = 921.12/x
  3. Step 3: Cross multiply
    1,230x = 1,698.48 × 921.12
  4. Step 4: Simplify right side
    1,230x = 1,564,503.90
  5. Step 5: Solve for x
    x = 1,564,503.90/1,230
  6. Step 6: Final answer
    x = 1,271.95

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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.