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Finding the Fourth Proportional to 1,229.28, 1,695.36 and 787.20

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Solution

The fourth proportional to 1,229.28, 1,695.36 and 787.20 is: 1,085.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,229.28 : 1,695.36 = 787.20 : x
  2. Step 2: Convert to fraction form
    1,229.28/1,695.36 = 787.20/x
  3. Step 3: Cross multiply
    1,229.28x = 1,695.36 × 787.20
  4. Step 4: Simplify right side
    1,229.28x = 1,334,587.39
  5. Step 5: Solve for x
    x = 1,334,587.39/1,229.28
  6. Step 6: Final answer
    x = 1,085.67

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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.