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Finding the Fourth Proportional to 1,228.78, 1,689.84 and 977.14

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Solution

The fourth proportional to 1,228.78, 1,689.84 and 977.14 is: 1,343.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,228.78 : 1,689.84 = 977.14 : x
  2. Step 2: Convert to fraction form
    1,228.78/1,689.84 = 977.14/x
  3. Step 3: Cross multiply
    1,228.78x = 1,689.84 × 977.14
  4. Step 4: Simplify right side
    1,228.78x = 1,651,210.26
  5. Step 5: Solve for x
    x = 1,651,210.26/1,228.78
  6. Step 6: Final answer
    x = 1,343.78

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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.