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Finding the Fourth Proportional to 1,242.70, 1,864.05 and 918.70

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Solution

The fourth proportional to 1,242.70, 1,864.05 and 918.70 is: 1,378.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,242.70 : 1,864.05 = 918.70 : x
  2. Step 2: Convert to fraction form
    1,242.70/1,864.05 = 918.70/x
  3. Step 3: Cross multiply
    1,242.70x = 1,864.05 × 918.70
  4. Step 4: Simplify right side
    1,242.70x = 1,712,502.74
  5. Step 5: Solve for x
    x = 1,712,502.74/1,242.70
  6. Step 6: Final answer
    x = 1,378.05

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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.