| 1 | True cost of Rwanda's coltan, higher than expected. | |
| 2 | Columbite-tantalite ore, better known as coltan, is found mainly in the rainforests of Africa and is used in the production of modern electronic devices. | |
| 3 | We have interest to buy tantalite, Ta2O5, coltan, columbite in Uganda and East African region. | |
| 4 | According to the Equal Tangents Theorem, AB is perpendicular to CB if there is only one other line that can be drawn from C that will be tangent to the circle. | |
| 5 | AB is a chord of a circle BC is a tangent at point B to point C. If AB is perpendicular to CB then there is only one other line which can be tangent to the circle . |