First we need to identify which trig ratio to use.
One of the known lengths (29) is adjacent to θ and the other length (21) is opposite to θ
Hence, we can use the tanratio to solve for θ
tanθ
=
oppositeadjacent
tanratio
tanθ
=
2129
Plug in the values
tanθ
=
0.724
Use the inverse function for tan on your calculator to get θ by itself
θ
=
tan-1(0.724)
The inverse of tan is tan-1
θ
=
35.9097
Use the shifttan function on your calculator
θ
=
35°54’35”
Use the degrees function on your calculator
θ
=
35°55’
Rounded to the nearest minute
θ=35°55’
Question 2 of 8
2. Question
Solve for x
Round your answer to one decimal place
x=(25.3)
Correct
Excellent!
Incorrect
Sin Ratio
sin=oppositehypotenuse
Cos Ratio
cos=adjacenthypotenuse
Tan Ratio
tan=oppositeadjacent
First we need to identify which trig ratio to use.
One of the known angles (56°) has 21 as an opposite side and x is the hypotenuse
Hence, we can use the sinratio to solve for x
sinθ
=
oppositehypotenuse
sinratio
sin(56°)
=
21x
Plug in the values
Get x by itself to find its value
sin(56°)
=
21x
x×sin(56°)
=
21
Multiply both sides by x
x
=
21sin(56°)
Divide both sides by sin(56°)
x
=
210.8290375726
Evaluate sin(56°) on the calculator
x
=
25.3
Round to one decimal place
x=25.3
Question 3 of 8
3. Question
Solve for θ
Round your answer to the nearest degree
θ=(73)°
Correct
Keep Going!
Incorrect
Sin Ratio
sin=oppositehypotenuse
Cos Ratio
cos=adjacenthypotenuse
Tan Ratio
tan=oppositeadjacent
First we need to identify which trig ratio to use.
One of the known lengths (8) is adjacent to θ and the other length (28) is the hypotenuse
Hence, we can use the cosratio to solve for θ
cosθ
=
adjacenthypotenuse
cosratio
cosθ
=
828
Plug in the values
cosθ
=
0.286
Use the inverse function for cos on your calculator to get θ by itself
θ
=
cos-1(0.286)
The inverse of cos is cos-1
θ
=
73.381°
Use the shiftcos function on your calculator
θ
=
73°
Rounded to the nearest degree
θ=73°
Question 4 of 8
4. Question
Find the length of d
The given measurements are in metres
Round your answer to the nearest whole number
d=(139) m
Hint
Help Video
Correct
Fantastic!
Incorrect
The Angles of Elevation and Depression are the angles created by the upward or downward slope of the hypotenuse.
The lines on top and bottom of the building are parallel, and the hypotenuse that cuts through it creates an angle of depression measured 47°10’
Since the angle of elevation (θ) is opposite of the angle of depression
(47°10’), θ is also equal to 47°10’
Next, we need to identify which trig ratio to use.
Angle θ has 150m as an opposite side and d as an adjacent side.
Hence, we can use the tanratio to solve for d
tanθ
=
oppositeadjacent
tanratio
tan47˚10’
=
150d
Plug in the values
d×1.0786
=
150
Cross multiply
d
=
1501.0786
Divide 1.0786 from both sides to isolate d
d
=
139m
d=139m
Question 5 of 8
5. Question
Find the area of the Triangle
The given measurements are in units
Round your answer to one decimal place
Area =(32.6)units2
Correct
Nice Job!
Incorrect
Area of a Triangle Formula
Area =12×b×c×sinA
Remember
Uppercase letters represent angles in the triangle
Lowercase letters represent the side lengths
Labelling the triangle
Solve for the area using the Area of a Triangle formula
A
=
12×b×c×sinA
Area of a Triangle formula
=
12×11.5×7×sin126°
Plug in the known lengths
=
32.6units2
Rounded to one decimal place
The given measurements are in units, so the area is measured as square units
Area=32.6units2
Question 6 of 8
6. Question
Solve for θ
Round your answer to the nearest minute
1.
2. 47˚15′
3. 67˚36′
4. 42˚45′
Hint
Help Video
Correct
Exceptional!
Incorrect
Sin Ratio
sin=oppositehypotenuse
Cos Ratio
cos=adjacenthypotenuse
Tan Ratio
tan=oppositeadjacent
First we need to identify which trig ratio to use.
One of the known lengths (4.9) is opposite to θ, and the other length (10.6) is adjacent to θ, but we only need half of that length to form a right triangle.
adjacent
=
10.6÷2
adjacent
=
5.3
Hence, we can use the tanratio to solve for θ
tanθ
=
oppositeadjacent
tanratio
tanθ
=
4.95.3
Plug in the values
tanθ
=
0.9243
Use the inverse function for tan on your calculator to get θ by itself
θ
=
tan-1(0.9243)
The inverse of tan is tan-1
θ
=
42.7543
Use the shifttan function on your calculator
θ
=
42°45’15”
Use the degrees function on your calculator
θ
=
42°45’
Rounded to the nearest minute
θ=42°45’
Question 7 of 8
7. Question
Find the area of the Triangle
The given measurements are in units
Round your answer to the nearest whole number
Area =(47)units2
Correct
Correct!
Incorrect
Area of a Triangle Formula
Area =12×a×c×sinB
Remember
Uppercase letters represent angles in the triangle
Lowercase letters represent the side lengths
Labelling the triangle
First, we need to find an angle between two sides with known values.
We can use the Sine Rule to find angle C
asinA
=
csinC
Sine Rule Formula
14sin77°
=
7sinC
Plug in the values
sinC×14
=
7×sin77°
Cross multiply
sinC
=
7×sin77°14
Divide 14 from each side to isolate sinC
sinC
=
6.82114
Simplify
sinC
=
0.487
Use the inverse function for sin on your calculator to get C by itself
C
=
sin-1(0.487)
The inverse of sin is sin-1
C
=
29.155
Use the shift sin function on your calculator
C
=
29.2°
Rounded to one decimal place
Now that we have the value of C, we can get the value of B by subtracting the total value of A and C to 180°, the total interior angle of a triangle
B
=
180°-(A+C)
B
=
180°-(77+29.2)
Plug in the known values
B
=
73.8°
Finally, solve for the area using the Area of a Triangle formula
Area
=
12×a×c×sinB
Area of a Triangle formula
=
12×14×7×sin73.8°
Plug in the known lengths
=
47.0units2
Rounded to one decimal place
The given measurements are in units, so the area is measured as square units
Area=47units2
Question 8 of 8
8. Question
Find the area of the Triangle
The given measurements are in units
Round your answer to the nearest whole number
Area =(92)units2
Correct
Great Work!
Incorrect
Area of a Triangle Formula
Area =12×b×c×sinA
Cosine Rule (finding an angle)
cosA=b2+c2−a22bc
Remember
Uppercase letters represent angles in the triangle
Lowercase letters represent the side lengths
Labelling the triangle
First, we need to find an angle to use for the Area of a Triangle formula
We can use the Cosine Rule (finding an angle) to solve for A
cosA
=
b2+c2−a22bc
Cosine Rule Formula
cosA
=
13.92+142−1622(13.9)(14)
Plug in known values
cosA
=
193.21+196-256389.2
Evaluate
cosA
=
0.342
Use the inverse function for cos on your calculator to get A by itself
A
=
cos-1(0.342)
The inverse of cos is cos-1
A
=
71.094
Use the shift cos function on your calculator
A
=
71.1°
Rounded to one decimal place
Finally, solve for the area using the Area of a Triangle formula
A
=
12×b×c×sinA
Area of a Triangle formula
=
12×13.9×14×sin71.1°
Plug in the known lengths
=
92units2
Rounded to one decimal place
The given measurements are in units, so the area is measured as square units