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Finding the Fourth Proportional to 690.40, 1,030.52 and 647.20

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Solution

The fourth proportional to 690.40, 1,030.52 and 647.20 is: 966.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 1,030.52 = 647.20 : x
  2. Step 2: Convert to fraction form
    690.40/1,030.52 = 647.20/x
  3. Step 3: Cross multiply
    690.40x = 1,030.52 × 647.20
  4. Step 4: Simplify right side
    690.40x = 666,952.54
  5. Step 5: Solve for x
    x = 666,952.54/690.40
  6. Step 6: Final answer
    x = 966.04

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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.