The Extant Greek Works of Apollonius of Perga, Vol. I

for the ratio of ηδ : ηγ = λϑ : κλ, that is, the demonstration omitted by Apollonius, that the triangles κϑλ and γηδ are similar, see p. 304, 17—19, and compare Pappus, Lemma VII.

III, 15:

A vertical series of geometric diagrams:
1. Two vertical line segments: the first labeled δ at the top and β at the bottom; the second labeled β at the top and ε at the bottom.
2. A square and a rectangle: the square has corners labeled δ (top-left), β (top-right), β (bottom-left), and δ (bottom-right); the rectangle to its right has corners labeled δ (top-left), β (top-right), and ε (bottom-right).
3. Two vertical line segments: the first labeled μ at the top and π at the bottom; the second labeled γ at the top and β at the bottom.
4. Two rectangles: the first labeled β, μ at top-left, π at top-right, and ϑ at both bottom corners; the second labeled β at top-left, γ at top-right, ϑ at bottom-left, and γ at bottom-right.
5. A square and a rectangle: the square has corners labeled η (top-left), ϑ (top-right), ϑ (bottom-left), and η (bottom-right); the rectangle to its right has corners labeled γ at top-left and top-right, β at bottom-left, and ϑ at bottom-right.

This series of figures illustrates what Apollonius has on p. 344, 14—24. In the codices V, v, and c, these discrepancies exist: before the first lines, V has

A horizontal diagram consisting of a rectangle, a vertical line, and another rectangle.

In the square δβ², Vc have β at the bottom, V omits it; for the lower δ, Vvc have ε; c alone has the line γβ; in the rectangle βϑ × μπ, Vvc add the letters η—ϑ on the lower side; c alone has the rectangle βγ × βϑ; in the square ηϑ², V omits all letters, Vc have the upper η, ϑ; for the rectangle γβ × βϑ, which V omitted, Vc have the triangle γβϑ; then v alone adds

Three right-angled triangles in a horizontal row. The first (left) is labeled with δ at the top vertex and β at the bottom-left vertex. The third (right) is labeled with η at the top vertex.

With these errors corrected, the result is: