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Finding the Fourth Proportional to 1,280.15, 1,920.23 and 915.65

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Solution

The fourth proportional to 1,280.15, 1,920.23 and 915.65 is: 1,373.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.15 : 1,920.23 = 915.65 : x
  2. Step 2: Convert to fraction form
    1,280.15/1,920.23 = 915.65/x
  3. Step 3: Cross multiply
    1,280.15x = 1,920.23 × 915.65
  4. Step 4: Simplify right side
    1,280.15x = 1,758,258.82
  5. Step 5: Solve for x
    x = 1,758,258.82/1,280.15
  6. Step 6: Final answer
    x = 1,373.48

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1.5x scale

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.