A 2-column table with 5 rows. Column 1 is labeled Number of friends helping with entries 0, 1, 2, 3, 4. Column 2 is labeled Hours to build tree house with entries 20, 20 minus 20 (0.10) = 18.0, 18 minus 18 (0.10) = 16.2, 16.2 minus 16.2 (0.10) = 14.6, question mark. Peter figures he can build the entire tree house by himself in 20 hours. He figures that each additional friend who helps him would improve the time by 10%. He created a table using the algebraic expression n – n(0.10), where n is the previous number of hours.

To the nearest tenth of an hour, how long will it take to build the tree house if 4 friends are helping?

Statement reason 1. δabc is similar to δced. given 2. 3. definition of slope 4. slope of slope of definition of slope 5. slope of × slope of multiplying the slopes 6. slope of × slope of substitution property of equality 7. slope of × slope of simplifying the right side the table contains the proof of the relationship between the slopes of two perpendicular lines. what is the reason for statement 2? a. parallel line segments that meet a common perpendicular line are proportional in length. b. the lengths of vertical and horizontal sides in congruent triangles are in a common ratio. c. trigonometric identities determine the lengths of the legs in a right triangle. d. corresponding side lengths in similar triangles are proportional in length.