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Finding the Fourth Proportional to 1,388.18, 1,915.08 and 915.47

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Solution

The fourth proportional to 1,388.18, 1,915.08 and 915.47 is: 1,262.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.18 : 1,915.08 = 915.47 : x
  2. Step 2: Convert to fraction form
    1,388.18/1,915.08 = 915.47/x
  3. Step 3: Cross multiply
    1,388.18x = 1,915.08 × 915.47
  4. Step 4: Simplify right side
    1,388.18x = 1,753,199.64
  5. Step 5: Solve for x
    x = 1,753,199.64/1,388.18
  6. Step 6: Final answer
    x = 1,262.95

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1.5x scale

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.