Home / 641-665

Finding the Third Proportional to 641 and 665

Calculator

Solution

The third proportional to 641 and 665 is: 689.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    641 : 665 = 665 : x
  2. Step 2: Convert to fraction form
    641/665 = 665/x
  3. Step 3: Cross multiply
    641x = 665 × 665
  4. Step 4: Simplify right side
    641x = 442,225
  5. Step 5: Solve for x
    x = 442,225/641
  6. Step 6: Final answer
    x = 689.90

Related Problems

Find third proportional to 320.50 and 332.50
Half scale
Find third proportional to 1,282 and 1,330
Double scale
Find third proportional to 643 and 667
Similar ratio
Find third proportional to 961.50 and 997.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.04) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.