5. One of the two parallel sides of a trapezium is half of the length of the other. If the height of the trapezium is 7cm and its area is 52.5cm^2. The length of the parallel sides are

5 and 10 cm

Step-by-step explanation:

The area (A) of a trapezium is calculated as

A = h (a + b)

where h is the height and a, b the parallel bases

Here A = 52.5, h = 7 and b = 0.5a ( half the length of the other ), thus

× 7 × (a + 0.5a) = 52.5, that is

3.5 × 1.5a = 52.5

5.25a = 52.5 ( divide both sides by 5.25 )

a = 10

Thus

The parallel sides are 10 cm and 5 cm

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.