The center of enlargement determines how every image vertex is positioned. For each original vertex, its directed distance from the center is multiplied by the same scale factor, so the image vertex follows that common relationship. Changing the center can therefore change the placement of the enlarged triangle, even when the scale factor remains unchanged.
Similarity is preserved because corresponding angles remain equal and corresponding side lengths share one scale factor. This allows the image to represent the same shape at a different size rather than a distorted figure. The distinction matters when using proportional relationships: lengths and perimeter follow the factor itself, whereas area follows the square of that factor.
A scale factor greater than one produces a larger triangle, while a factor between zero and one produces a smaller triangle. In either case, the same factor applies to every directed vertex distance and side length. This consistent change preserves the triangle’s proportions and provides a precise way to compare original and image sizes.
First choose the center of enlargement and identify the triangle’s three vertices. Measure or represent each vertex’s directed distance from that center, then multiply every distance by the selected scale factor. Mark the three resulting image vertices and connect them in corresponding order. The completed figure shows the transformed triangle and its preserved shape.
Corresponding side lengths in the original and image triangles are related by the same scale factor, creating useful proportional relationships. A known length can therefore be compared with its corresponding image length to determine relative size or support an indirect measurement. The same relationship also helps verify that a constructed image matches the intended enlargement.
The principles support construction diagrams, maps, and physical models by relating a represented size to an original or intended size. Because angles remain equal while lengths change predictably, the resulting figures retain the same shape. This makes enlargement useful whenever geometry must communicate or analyze objects at a different scale.
An enlargement provides a geometric way to express similarity: corresponding angles stay equal, and corresponding lengths maintain a common ratio. These properties connect transformations with proportional reasoning, allowing students to interpret similar triangles through both movement of vertices and numerical relationships. The connection is especially useful when explaining why a scaled diagram preserves shape while changing measurements.