Home / 401-687

Finding the Third Proportional to 401 and 687

Calculator

Solution

The third proportional to 401 and 687 is: 1,176.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    401 : 687 = 687 : x
  2. Step 2: Convert to fraction form
    401/687 = 687/x
  3. Step 3: Cross multiply
    401x = 687 × 687
  4. Step 4: Simplify right side
    401x = 471,969
  5. Step 5: Solve for x
    x = 471,969/401
  6. Step 6: Final answer
    x = 1,176.98

Related Problems

Find third proportional to 200.50 and 343.50
Half scale
Find third proportional to 802 and 1,374
Double scale
Find third proportional to 403 and 690
Similar ratio
Find third proportional to 601.50 and 1,030.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.71) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.