1. Stated problem: Draw five contour layers of the triangle plane (figure a). 2. The triangle vertices are given as points 4A(4), C'(7), and B'(0). We need to represent five contour layers (level curves) within this triangle. 3. Contour layers represent lines of constant value (elevation or function value) on the plane. To draw five layers, divide the range between the minimum and maximum vertex values into five equal intervals. 4. The values at vertices are 0 at B', 4 at 4A, and 7 at C'. The range is from 0 to 7. 5. Calculate contour levels: $$\text{levels} = 0, 1.4, 2.8, 4.2, 5.6, 7$$ 6. For each contour level, find points on the triangle edges where the plane's value equals the contour level by linear interpolation. 7. Connect these points inside the triangle to form contour lines. 8. This results in five contour layers inside the triangle, each representing a constant value. Final answer: Five contour layers correspond to values approximately 1.4, 2.8, 4.2, 5.6, and 7 inside the triangle defined by points B'(0), 4A(4), and C'(7).