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Finding the Fourth Proportional to 690.40, 952.72 and 421.35

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Solution

The fourth proportional to 690.40, 952.72 and 421.35 is: 581.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 952.72 = 421.35 : x
  2. Step 2: Convert to fraction form
    690.40/952.72 = 421.35/x
  3. Step 3: Cross multiply
    690.40x = 952.72 × 421.35
  4. Step 4: Simplify right side
    690.40x = 401,428.57
  5. Step 5: Solve for x
    x = 401,428.57/690.40
  6. Step 6: Final answer
    x = 581.44

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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.