Angles of a triangle always sum to how many degrees?
180 degrees
Two similar rectangles have widths 4 and 10. If the smaller rectangle’s length is 6, find the larger rectangle’s length.
Scale factor = 10/4 = 2.5
length = 6 × 2.5 = 15
If one triangle has sides of 8 inches and 4 inches and another triangle has sides of 4 inches and 2 inches and the included angles are congruent, what can you conclude about the triangles?
Yes, by SAS~
A flagpole’s shadow is 8 m long; a nearby 2 m stick casts a 2.5 m shadow. Using similarity, estimate the flagpole’s height.
Stick ratio: height/shadow = 2/2.5 = flagpole/8 → flagpole = 8 × (2/2.5) = 6.4 m
OR
Scale Factor: 8/2.5 = 3.2
flagpole = 3.2 × 2 = 6.4 m
In parallel lines cut by a transversal, what types of angles are congruent?
Corresponding, Alternate interior, and alternate exterior.
Name the similarity criterion that requires two pairs of corresponding angles to be equal for triangles to be similar
AA Similarity (AA~)
Why do you only need two angles to prove triangles are similar?
The third angle theorem proves that the third angles would also be congruent.
If a scale factor is > 1, will a dilated figure reduce or enlarge?
Enlarge
Opposite sides of a parallelogram are ______________ and ______________.
Parallel and congruent.
If triangle ABC is similar to triangle XYZ, list the congruent parts and the proportional parts.
Angle A is congruent to angle X, Angle B is congruent to angle Y, Angle C is congruent to Angle Z, AB is proportional to XY, BC is proportional to YZ, CA is proportional to ZX.
A model car is 1/18 the length of the real car. If the model is 11 inches long, how long is the real car in feet? (Round to nearest tenth.)
Real length = 11 × 18 = 198 in → 198/12 = 16.5 ft.
Two parallel lines are cut by a transversal creating corresponding angles. If one corresponding angle is 125°, what is its supplementary interior angle?
Supplementary interior angle = 55°
(because 180° + 125° = 55°)
Given triangle ABC and triangle DEF with
∠A = ∠D, ∠B = ∠E, and side AB = 5, side DE = 15, what is the scale factor from ABC to DEF?
3
If you know the measure of two sides of a right triangle, how do you find the third side?
Pythagorean Theorem. a^2 + b^2 = c^2
A scale drawing of a triangular lot has side lengths 8 cm, 6 cm, and 10 cm.
The actual lot has a longest side of 250 m. Determine the scale factor and the actual lengths of the other two sides in meters.
Scale factor = 250 m / 10 cm = 25 m per cm if longest side on drawing is 10 cm
Actual other sides: 8 cm × 25 = 200 m;
6 cm × 25 = 150 m.
Segment XY has length 10. After a dilation with scale factor 0.6, what is the new length?
10 × 0.6 = 6