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Finding the Fourth Proportional to 1,218.13, 1,680.96 and 687.09

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Solution

The fourth proportional to 1,218.13, 1,680.96 and 687.09 is: 948.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.13 : 1,680.96 = 687.09 : x
  2. Step 2: Convert to fraction form
    1,218.13/1,680.96 = 687.09/x
  3. Step 3: Cross multiply
    1,218.13x = 1,680.96 × 687.09
  4. Step 4: Simplify right side
    1,218.13x = 1,154,970.81
  5. Step 5: Solve for x
    x = 1,154,970.81/1,218.13
  6. Step 6: Final answer
    x = 948.15

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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.