Åk 6–9
 
English
4.4 Exercises – Calculating with Formulas and Functions
1. Circles
 

The formula for a circle’s circumference (perimeter) is C = p · d. Calculate the radius of the circle with a circumference of  45 cm.

   
 
 
2. Rectangles

The formula for a rectangles area is A = bh. Calculate h in a rectangle with an area of 180 cm2 and where b is 15 cm long.

 
 
3. Function of a Straight Line
As what point does the line intersect the y-axis?
a) y = 3x - 7
 
b) y = -5x
c) y = 2x + 4
d) 2y = 4x - 6
 
4. Parallel Lines

If two lines are parallel then there gradients are:

 
5. Parallel Lines

Which of the following lines are parallel?

a) y = 2x - 4
b) y = -5x - 1
c) y = -2x - 4
d) y = 7 + 2x
e) 2y = 4x - 8
f) y = 3 - 5x

 
6. Proportionality

Do the following functions describe a proportionality? Answer “Yes” or “No”.

a) y = 5 - 7x
b) y = -6x
c) 3y + 3 = 3 - 15x
d) 2y = 4x - 8