Home / 495.78-684.09-309.21

Finding the Fourth Proportional to 495.78, 684.09 and 309.21

Calculator

Solution

The fourth proportional to 495.78, 684.09 and 309.21 is: 426.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    495.78 : 684.09 = 309.21 : x
  2. Step 2: Convert to fraction form
    495.78/684.09 = 309.21/x
  3. Step 3: Cross multiply
    495.78x = 684.09 × 309.21
  4. Step 4: Simplify right side
    495.78x = 211,527.47
  5. Step 5: Solve for x
    x = 211,527.47/495.78
  6. Step 6: Final answer
    x = 426.66

Related Problems

Find fourth proportional to 247.89, 342.05 and 154.61
Half scale
Find fourth proportional to 991.56, 1,368.18 and 618.42
Double scale
Find fourth proportional to 496.78, 685.47 and 310.21
Similar ratio
Find fourth proportional to 743.67, 1,026.14 and 463.82
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.