1. **State the problem:** We need to find the area of the shaded region between two similar right triangles. 2. **Given data:** - Outer triangle base = 34.9 km - Outer triangle right side (hypotenuse) = 37.6 km - Inner triangle base = 23.3 km - Inner triangle right side (hypotenuse) = 25.1 km 3. **Formula for the area of a right triangle:** $$\text{Area} = \frac{1}{2} \times \text{base} \times \text{height}$$ 4. **Find the height of each triangle using the Pythagorean theorem:** For the outer triangle, let height be $h_o$: $$h_o = \sqrt{37.6^2 - 34.9^2} = \sqrt{1413.76 - 1218.01} = \sqrt{195.75} \approx 13.99$$ For the inner triangle, let height be $h_i$: $$h_i = \sqrt{25.1^2 - 23.3^2} = \sqrt{630.01 - 542.89} = \sqrt{87.12} \approx 9.33$$ 5. **Calculate the area of each triangle:** Outer triangle area: $$A_o = \frac{1}{2} \times 34.9 \times 13.99 = 0.5 \times 34.9 \times 13.99 = 244.26$$ Inner triangle area: $$A_i = \frac{1}{2} \times 23.3 \times 9.33 = 0.5 \times 23.3 \times 9.33 = 108.65$$ 6. **Find the shaded area by subtracting the inner area from the outer area:** $$\text{Shaded area} = A_o - A_i = 244.26 - 108.65 = 135.61$$ 7. **Round to the nearest hundredth:** $$\boxed{135.61}$$ square kilometers is the area of the shaded region.