Question

A scale drawing of a square object has a scale of 1 in. : 5 mm. The scale drawing has a length of 2.5 inches. Find the perimeter and the area of the object in the scale drawing. Then find the perimeter and area of the actual object.

Answer 1

The perimeter of the actual object is 50 mm.

The area of the actual object is 156.25 mm square

Explanation:

Given

Shape: Square

Scale: 1 in : 5 mm

Length of Scale Drawing = 2.5 in

Required:

- Perimeter of Actual Object

- Area of Actual Object

Calculating the perimeter of the actual object

Provided that the shape is a square;

The perimeter of the actual object is calculated by

Perimeter = 4 * Length

Recall that the scale is 1 in : 5 mm

This means 1 in on the scale represents 5 mm of the actual measurements of the object.

So, if 1 in ≈ 5 mm, then

2.5 in ≈ 2.5 * 5 mm

2.5 in = 12.5 mm

So, Length = 12.5mm

Now, the perimeter of the actual object can be calculated.

P = 4 * 12.5mm

P = 50mm

Hence, the perimeter of the actual measurements is 50 mm.

Calculating the area of the actual object

The area of the actual object is calculated by

Area = Length * Length

Recall that Length = 12.5 mm as calculated above

So,

Area = 12.5 * 12.5

Area = 156.25 mm square

Hence, the area of the actual object is 156.25 mm square

Answer 2

Perimeter and area of drawing

Perimeter= 10 In

Area = 6.25 In²

Perimeter and area of object

Perimeter = 51.836 mm

Area = 167.936 mm²

Explanation:

We are dealing with a square object, so let's talk about the drawing first.

The length of one side = 2.5 In

Perimeter of square= 4L

Perimeter = 4*2.5

Perimeter= 10 In

Area = L*L

Area = 2.5*2.5

Area = 6.25 In²

Letd note that 1 inch =

25.4 millimetres

So 2.5 Inch = 2.5 * 25.4

2.5 In = 63.5 mm.

25.4 mm is to 5mm

63.5 mm is to (63.5*5)/24.5

63.5mm is to 12.959 mm

So the length of actual object is 12.959mm

The perimeter = 4*12.959

Perimeter = 51.836 mm

Area = 12.959²

Area = 167.936 mm²