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44
BOOK I. PROP. XLIV. THEOR.
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O a given straight line (
) to apply a parallelogram gram equal to a given triangle ( ), and having an angle equal to a given rectilinear angle ( ).
Make = with = (pr. 42.)
and having one of its fides conterminous
with and in continuation of.
Produce till it meets ∥
draw produce it till if meets continued ;
draw ∥ meeting
produced, and produce.
= (pr. 43)
but = (conft.)
∴ = ; and
= = = (pr. 19. and const.)
Q. E. D.
