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Finding the Fourth Proportional to 1,388.40, 1,915.08 and 864.08

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Solution

The fourth proportional to 1,388.40, 1,915.08 and 864.08 is: 1,191.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.40 : 1,915.08 = 864.08 : x
  2. Step 2: Convert to fraction form
    1,388.40/1,915.08 = 864.08/x
  3. Step 3: Cross multiply
    1,388.40x = 1,915.08 × 864.08
  4. Step 4: Simplify right side
    1,388.40x = 1,654,782.33
  5. Step 5: Solve for x
    x = 1,654,782.33/1,388.40
  6. Step 6: Final answer
    x = 1,191.86

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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.