Home / 479.80-661.81-399.84

Finding the Fourth Proportional to 479.80, 661.81 and 399.84

Calculator

Solution

The fourth proportional to 479.80, 661.81 and 399.84 is: 551.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    479.80 : 661.81 = 399.84 : x
  2. Step 2: Convert to fraction form
    479.80/661.81 = 399.84/x
  3. Step 3: Cross multiply
    479.80x = 661.81 × 399.84
  4. Step 4: Simplify right side
    479.80x = 264,618.11
  5. Step 5: Solve for x
    x = 264,618.11/479.80
  6. Step 6: Final answer
    x = 551.52

Related Problems

Find fourth proportional to 239.90, 330.91 and 199.92
Half scale
Find fourth proportional to 959.60, 1,323.62 and 799.68
Double scale
Find fourth proportional to 480.80, 663.19 and 400.84
Similar ratio
Find fourth proportional to 719.70, 992.72 and 599.76
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.