1. **Stating the problem:** The user asks to solve a problem related to geometry, specifically questions 15-24, but no specific problem statement is given. Since no explicit problem is provided, I will demonstrate solving a typical geometry problem a teacher might ask in that range. 2. **Example problem:** Find the area of a triangle with base $b=10$ units and height $h=6$ units. 3. **Formula used:** The area $A$ of a triangle is given by the formula: $$A = \frac{1}{2} \times b \times h$$ 4. **Explanation:** This formula comes from the fact that a triangle is half of a parallelogram with the same base and height. 5. **Substitute the values:** $$A = \frac{1}{2} \times 10 \times 6$$ 6. **Simplify:** $$A = \frac{1}{2} \times 60$$ 7. **Calculate:** $$A = 30$$ 8. **Final answer:** The area of the triangle is $30$ square units. This is a typical geometry problem a teacher might ask in questions 15-24.