Math & Science ACT Workuot

(Marvins-Underground-K-12) #1
53 . D Draw the triangle to determine that side YZ is opposite X, and side XZ is opposite Y.

Using the law of sines, set up the proportion: . Multiply both sides by

sin57° to get YZ = . Choice (C) does not use the correct angle-side pairs, and (A),

(B), and (E) use the incorrect proportions.

56 . F The correct answer is (F). We can use SOHCAHTOA and a right triangle to defeat this

seemingly hard problem. Draw a right triangle and mark in angle θ. If cosθ = , that means

the adjacent side is 3, and the hypotenuse is 4. Now use the Pythagorean theorem to find the

third side: 3^2 + b^2 = 4^2 , so 9 + b^2 = 16, which simplifies to b^2 = 7 and finally to b = .

Your sketch should look something like this:

Now just plug your dimensions into the functions: sinθ tanθ = .

58 . J In the standard (x,y) coordinate plane, the sine of an angle in Quadrant II is always positive,

eliminating (F), (G), and (H). Make a right triangle with the x-axis, which gives you a 5-12-

13 triangle. The angle θ is at the origin, so the leg opposite the angle is 5 and the hypotenuse

is 13. Sine is defined as “opposite over hypotenuse,” which in this case gives , so the

answer is (J).

59 . D The range of sin x is normally between −1 to 1, inclusive; however, the range can change

depending on the graph’s amplitude and vertical shift. In the general form A sin(Bx + C) + D,
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