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Finding the Fourth Proportional to 1,313.55, 1,812.65 and 840.78

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Solution

The fourth proportional to 1,313.55, 1,812.65 and 840.78 is: 1,160.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,313.55 : 1,812.65 = 840.78 : x
  2. Step 2: Convert to fraction form
    1,313.55/1,812.65 = 840.78/x
  3. Step 3: Cross multiply
    1,313.55x = 1,812.65 × 840.78
  4. Step 4: Simplify right side
    1,313.55x = 1,524,035.66
  5. Step 5: Solve for x
    x = 1,524,035.66/1,313.55
  6. Step 6: Final answer
    x = 1,160.24

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1.5x scale

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.