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Finding the Fourth Proportional to 870.72, 1,298.40 and 749.76

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Solution

The fourth proportional to 870.72, 1,298.40 and 749.76 is: 1,118.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.72 : 1,298.40 = 749.76 : x
  2. Step 2: Convert to fraction form
    870.72/1,298.40 = 749.76/x
  3. Step 3: Cross multiply
    870.72x = 1,298.40 × 749.76
  4. Step 4: Simplify right side
    870.72x = 973,488.38
  5. Step 5: Solve for x
    x = 973,488.38/870.72
  6. Step 6: Final answer
    x = 1,118.03

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.