7-4 and 7-5 Geometry

7-4 Triangle Angle Bisector Theorem

An angle bisector of a triangle divides the opposite side into two segments whose lengths are proportional to the lengths of the other two sides.

7-5 Indirect Measurement Definition

Any method that uses - formulas - similar figures - proportions to measure an object

7-4 Converse of the Triangle Proportionality Theorem

If a line divides two sides of a triangle proportionally, then it is parallel to the third side

7-4 Triangle Proportionality Theorem

If line parallel to a side of triangle intersects the other 2 sides, then it divides the sides proportionally

7-5 Proportional Perimeters and Areas Theorem

If the similarity ratio of 2 similar figures is a/b, then the ratio of their perimeters is a/b and the ratio of their areas is (a/b) squared = a squared/b squared

7-4 Two-Transversal Proportionality Corollary

If three or more parallel lines intersect two transversals, then they divide the transversals proportionally.

7-5 Scale Drawing Definition

Represents an object as smaller than or larger than its actual size. The drawing's scale is the ratio of any length in the drawing to the corresponding actual length.

7-5 Remember: scale drawing and units of measure

Scale drawing may compare measurements that have different units of measure.

7-5 Similar Triangles: similarity, perimeter and area ratio

for similar triangles: SAME ratio for each pair of corresponding sides of similar triangles, a/b SAME ratio of the perimeters, a/b Ratio of areas is (a/b) squared = a squared/b squared