Home / 688.05-1,031.40-615.15

Finding the Fourth Proportional to 688.05, 1,031.40 and 615.15

Calculator

Solution

The fourth proportional to 688.05, 1,031.40 and 615.15 is: 922.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.05 : 1,031.40 = 615.15 : x
  2. Step 2: Convert to fraction form
    688.05/1,031.40 = 615.15/x
  3. Step 3: Cross multiply
    688.05x = 1,031.40 × 615.15
  4. Step 4: Simplify right side
    688.05x = 634,465.71
  5. Step 5: Solve for x
    x = 634,465.71/688.05
  6. Step 6: Final answer
    x = 922.12

Related Problems

Find fourth proportional to 344.03, 515.70 and 307.58
Half scale
Find fourth proportional to 1,376.10, 2,062.80 and 1,230.30
Double scale
Find fourth proportional to 689.05, 1,032.90 and 616.15
Similar ratio
Find fourth proportional to 1,032.08, 1,547.10 and 922.73
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.