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Finding the Fourth Proportional to 1,287.16, 1,775.34 and 815.13

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Solution

The fourth proportional to 1,287.16, 1,775.34 and 815.13 is: 1,124.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.16 : 1,775.34 = 815.13 : x
  2. Step 2: Convert to fraction form
    1,287.16/1,775.34 = 815.13/x
  3. Step 3: Cross multiply
    1,287.16x = 1,775.34 × 815.13
  4. Step 4: Simplify right side
    1,287.16x = 1,447,125.40
  5. Step 5: Solve for x
    x = 1,447,125.40/1,287.16
  6. Step 6: Final answer
    x = 1,124.28

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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.