Glass mirrors were the latest cutting edge technology in the middle ages, but the convex mirror was the only shape possible.

玻璃子中世纪最新的尖端技术，但凸唯一可能的形状。

It did have kind of these convex mirrors.

它确实有这种凸。

These mirrors are convex, causing rays to converge into a real image, which is then magnified through an eyepiece or projected directly onto a digital sensor.

这些子凸的，使光线会聚 成真实图像，然后通过 目放大或直接投字传感器上。

Remember, the substance of  what she's found so far is that if you look at any convex solid, then the average area for its shadow  is going to be proportional to its surface area.

请记住，目前为止她发现的实质内容， 如果您观察任何凸实体，那么其阴影的平均积将与其表积成正比。