Triangle Projection
1. We are given a triangle ABC with a right angle at H, where H is the projection of A on BC, and AH is perpendicular to BC.
2. Given lengths: AB = 6, BH = 4, HC = 5.
3. Since BH + HC = BC, we find BC = 4 + 5 = 9.
4. The right angle at H indicates AH \perp BC, so triangle ABH and AHC are right-angled triangles.
5. Using Pythagoras on triangle ABH: $$AB^2 = AH^2 + BH^2\Rightarrow 6^2 = AH^2 + 4^2\Rightarrow 36 = AH^2 + 16\Rightarrow AH^2 = 20\Rightarrow AH = \sqrt{20}=2\sqrt{5}.$$
6. Using Pythagoras on triangle AHC: $$AC^2 = AH^2 + HC^2\Rightarrow AC^2 = 20 + 25 = 45\Rightarrow AC = 3\sqrt{5}.$$
7. Verify coordinate locations:
- Point A is given as (-2,1)
- Point B is (2,3)
8. Vector \vec{AB} = (2 - (-2), 3 - 1) = (4,2).
9. We can find length AB from coordinates: $$\sqrt{4^2 + 2^2} = \sqrt{16 + 4} = \sqrt{20} = 2\sqrt{5}.$$ This differs from given AB = 6, which suggests coordinates are illustrative but lengths are definitive.
10. Summary:
- Length BC = 9
- Length BH = 4, HC = 5
- Length AH = 2\sqrt{5}
- Length AB = 6
- Length AC = 3\sqrt{5}
This completes the geometric analysis based on given data.