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Finding the Fourth Proportional to 1,313.38, 1,811.78 and 840.78

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Solution

The fourth proportional to 1,313.38, 1,811.78 and 840.78 is: 1,159.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,313.38 : 1,811.78 = 840.78 : x
  2. Step 2: Convert to fraction form
    1,313.38/1,811.78 = 840.78/x
  3. Step 3: Cross multiply
    1,313.38x = 1,811.78 × 840.78
  4. Step 4: Simplify right side
    1,313.38x = 1,523,312.07
  5. Step 5: Solve for x
    x = 1,523,312.07/1,313.38
  6. Step 6: Final answer
    x = 1,159.84

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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.