Question

Difficulty: EasyPerimeter and Area of Plane Shapes

A rhombus has diagonals of lengths 12 cm12\text{ cm} and 16 cm16\text{ cm}. What is the perimeter of the rhombus in cm\text{cm}?

Answer: 40 cm

Answer

The perimeter of the rhombus is 40 cm40\text{ cm}.
The diagonals of a rhombus bisect each other at right angles, dividing the rhombus into four congruent right-angled triangles. Each triangle has legs measuring 6 cm6\text{ cm} and 8 cm8\text{ cm}. Applying the Pythagorean theorem, the hypotenuse (which is the side length of the rhombus) is 62+82=100=10 cm\sqrt{6^2 + 8^2} = \sqrt{100} = 10\text{ cm}. Since all four sides of a rhombus are equal, the perimeter is 4×10=40 cm4 \times 10 = 40\text{ cm}.

Step-by-Step Solution

1
Calculate the lengths of the semi-diagonals
The semi-diagonals are 6 cm6\text{ cm} and 8 cm8\text{ cm}.
The diagonals of a rhombus bisect each other perpendicularly.
2
Determine the side length of the rhombus using the Pythagorean theorem
Side length s=62+82=100=10 cms = \sqrt{6^2 + 8^2} = \sqrt{100} = 10\text{ cm}.
Each side of the rhombus forms the hypotenuse of a right-angled triangle formed by the semi-diagonals.
3
Calculate the total perimeter
Perimeter P=4×10=40 cmP = 4 \times 10 = 40\text{ cm}.
All four sides of a rhombus are equal in length.

Key Concept

Perimeter of a rhombus derived from diagonal lengths using right-triangle properties
Estimated Time:1m 0s
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