Digital ACT Reading Practice Question #1731

As it is used in the passage, the word "orthogonal" refers to lines that: Passage Excerpt (Humanities): Around 1415, in the shadow of Florence's unfinished cathedral dome, Filippo Brunelleschi conducted an experiment that permanently restructured Western visual representation. Standing inside Santa Maria del Fiore, Brunelleschi held a painted panel of the Baptistery. In the center was a small peep-hole; holding the painting backward against his eye, he looked through at a mirror held in front. When he removed the mirror, his direct sight of the actual Baptistery matched his painted reflection with optical exactitude. By establishing a single vanishing point along a horizon line where orthogonal lines converge, Brunelleschi transformed the picture plane from a decorative tapestry into a rationalized window onto three-dimensional space, fusing vision with empirical geometry.