Home / 402.40-555-309

Finding the Fourth Proportional to 402.40, 555 and 309

Calculator

Solution

The fourth proportional to 402.40, 555 and 309 is: 426.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    402.40 : 555 = 309 : x
  2. Step 2: Convert to fraction form
    402.40/555 = 309/x
  3. Step 3: Cross multiply
    402.40x = 555 × 309
  4. Step 4: Simplify right side
    402.40x = 171,495
  5. Step 5: Solve for x
    x = 171,495/402.40
  6. Step 6: Final answer
    x = 426.18

Related Problems

Find fourth proportional to 201.20, 277.50 and 154.50
Half scale
Find fourth proportional to 804.80, 1,110 and 618
Double scale
Find fourth proportional to 403.40, 556.38 and 310
Similar ratio
Find fourth proportional to 603.60, 832.50 and 463.50
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.