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Finding the Fourth Proportional to 1,138.21, 1,570.15 and 665.79

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Solution

The fourth proportional to 1,138.21, 1,570.15 and 665.79 is: 918.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.21 : 1,570.15 = 665.79 : x
  2. Step 2: Convert to fraction form
    1,138.21/1,570.15 = 665.79/x
  3. Step 3: Cross multiply
    1,138.21x = 1,570.15 × 665.79
  4. Step 4: Simplify right side
    1,138.21x = 1,045,390.17
  5. Step 5: Solve for x
    x = 1,045,390.17/1,138.21
  6. Step 6: Final answer
    x = 918.45

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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.