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Finding the Fourth Proportional to 1,218.76, 1,681.72 and 687.56

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Solution

The fourth proportional to 1,218.76, 1,681.72 and 687.56 is: 948.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.76 : 1,681.72 = 687.56 : x
  2. Step 2: Convert to fraction form
    1,218.76/1,681.72 = 687.56/x
  3. Step 3: Cross multiply
    1,218.76x = 1,681.72 × 687.56
  4. Step 4: Simplify right side
    1,218.76x = 1,156,283.40
  5. Step 5: Solve for x
    x = 1,156,283.40/1,218.76
  6. Step 6: Final answer
    x = 948.74

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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.