Home / 921-1,381.56-408

Finding the Fourth Proportional to 921, 1,381.56 and 408

Calculator

Solution

The fourth proportional to 921, 1,381.56 and 408 is: 612.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    921 : 1,381.56 = 408 : x
  2. Step 2: Convert to fraction form
    921/1,381.56 = 408/x
  3. Step 3: Cross multiply
    921x = 1,381.56 × 408
  4. Step 4: Simplify right side
    921x = 563,676.48
  5. Step 5: Solve for x
    x = 563,676.48/921
  6. Step 6: Final answer
    x = 612.03

Related Problems

Find fourth proportional to 460.50, 690.78 and 204
Half scale
Find fourth proportional to 1,842, 2,763.12 and 816
Double scale
Find fourth proportional to 922, 1,383.06 and 409
Similar ratio
Find fourth proportional to 1,381.50, 2,072.34 and 612
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.