Question

7a. Find the PERIMETER of the figure.

6 mm
2 mm
2 mm
a) 14.42 mm
b) 19.42 mm
c) 24.84 mm
d) 13.84 mm

Answer 1

The answer is b. 19.42. :)

Answer 2

The Perimeter figure is: 21.42 mm

Explanation:

The given figure consists of two parts:

1) Semicircle

2) Square

Determining the Perimeter of the Semicircle:

Given

Diameter d = 6 mm

Radius r = d/2 = 6/2 = 3 mm

In a semi-circle, the perimeter is made up of half the circumference (arc) of the circle and the diameter of the circle.

Perimeter = 1/2 × ( circumference of the circle ) + d

= 1/2 × (2πr) + d

= πr + d

= 3.14(3) + 6

= 9.42 + 6

= 15.42 mm

Thus, the Perimeter of the semi-circle is: 15.42 mm

Determining the Perimeter of the Square:

Given

Length of a side = a = 2mm

Perimeter of square = 4a = 4(2) = 8mm

Thus, the Perimeter of the Square is: 8mm

Now, in order to determine the Perimeter of a complete figure, we need to add the Perimeter of the square and the perimeter of the semicircle and subtract 2 mm.

The reason why we need to subtract 2mm because one side of the square (2mm) is overlapped along the diameter of the semicircle.

Now,

Figure Perimeter = Perimeter of square + Perimeter of Semicircle - 2

= 8 + 15.42 - 2

= 21.42 mm

Therefore, the Perimeter figure is: 21.42 mm

Note: It seems you may have missed adding the correct choice there.