Home / 723.90-1,085.49-399

Finding the Fourth Proportional to 723.90, 1,085.49 and 399

Calculator

Solution

The fourth proportional to 723.90, 1,085.49 and 399 is: 598.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    723.90 : 1,085.49 = 399 : x
  2. Step 2: Convert to fraction form
    723.90/1,085.49 = 399/x
  3. Step 3: Cross multiply
    723.90x = 1,085.49 × 399
  4. Step 4: Simplify right side
    723.90x = 433,110.51
  5. Step 5: Solve for x
    x = 433,110.51/723.90
  6. Step 6: Final answer
    x = 598.30

Related Problems

Find fourth proportional to 361.95, 542.75 and 199.50
Half scale
Find fourth proportional to 1,447.80, 2,170.98 and 798
Double scale
Find fourth proportional to 724.90, 1,086.99 and 400
Similar ratio
Find fourth proportional to 1,085.85, 1,628.24 and 598.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.