The chapter on cosine is very interesting but also important. To check students’ understanding, a math test in the fourth grade on trigonometry in the triangle and the cosine (cos ) of an acute angle is necessary. During this evaluation, the teacher will have the opportunity to check if the students have assimilated the course.
Solve each of the following equations:
a) 8 + x = – 4
b) 5 x – 6 = 10
What number must be added to the numerator and denominator of to obtain the fraction ?
(3,5points) ‘the cosine’.
ABC is a right triangle at A.
a) Make a full-scale figure and plot the data on it,
b) Calculate an approximate value of the length AB rounded to the hundredth .
BC = 10 cm = 36°.
c) calculate the length AC .
(1,5points) ‘the cosine’.
DEF is a right triangle in D
Make a freehand figure.
We have. DE = 8 cm = 31° Calculate EF.
a)Prove that triangle ABC is a rectangle. specify in which point.
We have: AB = 30 cm AC = 12.5 cm BC = 32.5 cm.
b) Calculate cos .
Deduce a value of the angle to the nearest degree.
The length x of a rectangle, in centimeters, exceeds its width by 4 cm.
a) Write its width as a function of x.
b) Write the perimeter of this rectangle as a function of x.
c) Calculate x when this perimeter measures 140 cm.
In a pastry shop, a custard tart is sold in slices.
This is the price of one share.
After having sold 3.80 €, there are 5 shares left.
After having sold 5 €, there are 4 shares left.
1. Reproduce and complete the equality :
5 x + 3,80 = …………
which translates the price of a pie in two ways.
2. Solve the resulting equation to determine the price of a unit.
3. Calculate the number of slices that can be made in a pie.
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