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Finding the Fourth Proportional to 870.17, 1,299.56 and 782.69

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Solution

The fourth proportional to 870.17, 1,299.56 and 782.69 is: 1,168.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.17 : 1,299.56 = 782.69 : x
  2. Step 2: Convert to fraction form
    870.17/1,299.56 = 782.69/x
  3. Step 3: Cross multiply
    870.17x = 1,299.56 × 782.69
  4. Step 4: Simplify right side
    870.17x = 1,017,142.21
  5. Step 5: Solve for x
    x = 1,017,142.21/870.17
  6. Step 6: Final answer
    x = 1,168.91

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.