Home / 685-991

Finding the Third Proportional to 685 and 991

Calculator

Solution

The third proportional to 685 and 991 is: 1,433.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    685 : 991 = 991 : x
  2. Step 2: Convert to fraction form
    685/991 = 991/x
  3. Step 3: Cross multiply
    685x = 991 × 991
  4. Step 4: Simplify right side
    685x = 982,081
  5. Step 5: Solve for x
    x = 982,081/685
  6. Step 6: Final answer
    x = 1,433.69

Related Problems

Find third proportional to 342.50 and 495.50
Half scale
Find third proportional to 1,370 and 1,982
Double scale
Find third proportional to 687 and 994
Similar ratio
Find third proportional to 1,027.50 and 1,486.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.45) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.