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Finding the Fourth Proportional to 1,187.05, 1,638.28 and 689.59

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Solution

The fourth proportional to 1,187.05, 1,638.28 and 689.59 is: 951.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,187.05 : 1,638.28 = 689.59 : x
  2. Step 2: Convert to fraction form
    1,187.05/1,638.28 = 689.59/x
  3. Step 3: Cross multiply
    1,187.05x = 1,638.28 × 689.59
  4. Step 4: Simplify right side
    1,187.05x = 1,129,741.51
  5. Step 5: Solve for x
    x = 1,129,741.51/1,187.05
  6. Step 6: Final answer
    x = 951.72

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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.