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Finding the Fourth Proportional to 1,312.05, 1,966.35 and 1,128.20

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Solution

The fourth proportional to 1,312.05, 1,966.35 and 1,128.20 is: 1,690.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,312.05 : 1,966.35 = 1,128.20 : x
  2. Step 2: Convert to fraction form
    1,312.05/1,966.35 = 1,128.20/x
  3. Step 3: Cross multiply
    1,312.05x = 1,966.35 × 1,128.20
  4. Step 4: Simplify right side
    1,312.05x = 2,218,426.24
  5. Step 5: Solve for x
    x = 2,218,426.24/1,312.05
  6. Step 6: Final answer
    x = 1,690.81

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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.