Home / 709.87-979.40-399.31

Finding the Fourth Proportional to 709.87, 979.40 and 399.31

Calculator

Solution

The fourth proportional to 709.87, 979.40 and 399.31 is: 550.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.87 : 979.40 = 399.31 : x
  2. Step 2: Convert to fraction form
    709.87/979.40 = 399.31/x
  3. Step 3: Cross multiply
    709.87x = 979.40 × 399.31
  4. Step 4: Simplify right side
    709.87x = 391,082.22
  5. Step 5: Solve for x
    x = 391,082.22/709.87
  6. Step 6: Final answer
    x = 550.92

Related Problems

Find fourth proportional to 354.94, 489.70 and 199.66
Half scale
Find fourth proportional to 1,419.74, 1,958.79 and 798.62
Double scale
Find fourth proportional to 710.87, 980.77 and 400.31
Similar ratio
Find fourth proportional to 1,064.81, 1,469.09 and 598.97
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.