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Finding the Fourth Proportional to 781.65, 1,177.84 and 647.69

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Solution

The fourth proportional to 781.65, 1,177.84 and 647.69 is: 975.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.65 : 1,177.84 = 647.69 : x
  2. Step 2: Convert to fraction form
    781.65/1,177.84 = 647.69/x
  3. Step 3: Cross multiply
    781.65x = 1,177.84 × 647.69
  4. Step 4: Simplify right side
    781.65x = 762,875.19
  5. Step 5: Solve for x
    x = 762,875.19/781.65
  6. Step 6: Final answer
    x = 975.98

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.