Right Triangles and Trigonometry Flashcards
7 cards from real Bluebook SAT Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Right Triangles and Trigonometry flashcards as text
In right triangle XYZ with right angle at Z, XZ = 8 and XY = 17. What is cos(X)?
Answer: 8/17
XZ = 8 is adjacent to X and XY = 17 is the hypotenuse, so cos(X) = adjacent/hypotenuse = 8/17.
A surveyor looks up at the top of a flagpole. The angle of elevation is 30° and the surveyor is 45 feet from the base. How tall is the flagpole?
Answer: 15√3
tan(30°) = height/45, so height = 45·tan(30°) = 45·(1/√3) = 45/√3 = 45√3/3 = 15√3.
A right triangle has a hypotenuse of 13 and one leg of 5. What is the sine of the larger acute angle?
Answer: 12/13
The other leg = √(169 − 25) = 12. The larger acute angle is opposite the longer leg (12), so sin = 12/13.
In a 45-45-90 right triangle, if one leg has length 5, what is the length of the hypotenuse?
Answer: 5√2
In a 45-45-90 triangle, hypotenuse = leg × √2 = 5√2.
Right triangle DEF has right angle at E. If tan(D) = 3 and EF = 6, what is DF?
Answer: 2√10
tan(D) = EF/DE = 6/DE = 3, so DE = 2. Then DF = √(DE² + EF²) = √(4 + 36) = √40 = 2√10.
In right triangle ABC with right angle at C, angle A = 30° and AB = 12. What is the length of BC?
Answer: 6
sin(30°) = BC/AB = BC/12, so BC = 12 × sin(30°) = 12 × 0.5 = 6.
In right triangle PQR with the right angle at R, PQ = 29 and QR = 21. What is sin(Q)?
Answer: 20/29
PR = √(PQ² − QR²) = √(841 − 441) = √400 = 20. sin(Q) = PR/PQ = 20/29.