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Finding the Fourth Proportional to 1,312.56, 1,811.48 and 781.57

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Solution

The fourth proportional to 1,312.56, 1,811.48 and 781.57 is: 1,078.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,312.56 : 1,811.48 = 781.57 : x
  2. Step 2: Convert to fraction form
    1,312.56/1,811.48 = 781.57/x
  3. Step 3: Cross multiply
    1,312.56x = 1,811.48 × 781.57
  4. Step 4: Simplify right side
    1,312.56x = 1,415,798.42
  5. Step 5: Solve for x
    x = 1,415,798.42/1,312.56
  6. Step 6: Final answer
    x = 1,078.65

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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.