Home / 1,218.11-1,681.16-721.17

Finding the Fourth Proportional to 1,218.11, 1,681.16 and 721.17

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Solution

The fourth proportional to 1,218.11, 1,681.16 and 721.17 is: 995.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,218.11 : 1,681.16 = 721.17 : x
  2. Step 2: Convert to fraction form
    1,218.11/1,681.16 = 721.17/x
  3. Step 3: Cross multiply
    1,218.11x = 1,681.16 × 721.17
  4. Step 4: Simplify right side
    1,218.11x = 1,212,398.55
  5. Step 5: Solve for x
    x = 1,212,398.55/1,218.11
  6. Step 6: Final answer
    x = 995.32

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Half scale
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Double scale
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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.