The base of a certain solid is the triangle with vertices at (-10,5), (5,5), and the origin. Cross-sections perpendicular to the y-axis are squares.

You have not asked a question. Your figure sounds like a tilted tetrahedron, lying on one triangular side at z = 0 (the x,y plane). There is a 15 x 15 square base at y = 5, and an apex at (0,0,0)

To determine the shape and dimensions of the solid, we need to examine the given information and make use of some geometric concepts.

First, let's visualize the given triangle. The vertices are (-10,5), (5,5), and (0,0). Plotted on a graph, they create a base triangle that lies on the x-axis, with a right angle at the origin.

Now, let's consider the cross-sections perpendicular to the y-axis. Since the cross-sections are squares, they will have equal lengths on both sides.

Since the cross-sections are perpendicular to the y-axis, their sides will be parallel to the x-axis. Hence, the cross-section squares will have two sides on the x-axis and two sides perpendicular to it.

To find the side lengths of the cross-section squares, we need to determine the length of the corresponding segment parallel to the x-axis for each y-coordinate. The key observation here is that the y-coordinate remains constant along segments that are parallel to the x-axis.

Let's analyze the triangle and find the lengths of each segment parallel to the x-axis for different y-coordinates.

1. For a y-coordinate of 5, the segment length parallel to the x-axis is the difference between the x-coordinates of the two vertices on the x-axis: 5 - (-10) = 15.

2. For a y-coordinate of 0, the segment length parallel to the x-axis is the x-coordinate of the vertex at (5,5): 5.

Given that the cross-sections perpendicular to the y-axis are squares, we now know that the side lengths of these squares will vary with y-coordinate. Specifically, the length will be 15 when y = 5 and 5 when y = 0.

Therefore, the shape of the solid is a triangular prism, where the base is a right-angled triangle with sides of length 15 and 5, and the height of the prism will be determined by the range of y-coordinates.

Note: If the range of y-coordinates is not mentioned, it is not possible to determine the exact dimensions of the triangular prism, only the relationship between the base and the cross-section squares.