Join 60,000+ competitive exam aspirants
The diagonal of a rhombus is 14 cm and 48 cm. What is the perimeter of the rhombus?
100 cm
120 cm
96 cm
112 cm
100 cm
Use the half-diagonal Pythagorean triplet: half-diagonals are 7 cm and 24 cm, forming the standard (7,24,25) right-angled triangle where side s=25 cm.
Diagonals of the rhombus are d1тАЛ=14 cm and d2тАЛ=48 cm.
P=4├Ч(2d1тАЛтАЛ)2+(2d2тАЛтАЛ)2тАЛ
Use the half-diagonal Pythagorean triplet: half-diagonals are 7 cm and 24 cm, forming the standard (7,24,25) right-angled triangle where side s=25 cm.
Students often forget to halve the diagonals before applying the Pythagorean theorem, using 14 and 48 directly instead of 7 and 24.
Identify Properties of a Rhombus
The diagonals of a rhombus bisect each other at right angles (90┬░), dividing the rhombus into four congruent right-angled triangles.
Angle┬аbetween┬аdiagonals┬а=90┬░
Find the Half-Diagonals
Divide each given diagonal by 2 to get the lengths of the legs of the right-angled triangle: 214тАЛ=7 cm and 248тАЛ=24 cm.
r1тАЛ=7┬аcm,r2тАЛ=24┬аcm
Calculate Side Length using Pythagoras Theorem
Apply the Pythagorean theorem to find the side length s of the rhombus: s=72+242тАЛ=49+576тАЛ=625тАЛ=25 cm.
s=72+242тАЛ=25┬аcm
Calculate the Perimeter
Since all four sides of a rhombus are equal, multiply the side length by 4 to get the total perimeter: P=4├Ч25=100 cm.
P=4├Ч25=100┬аcm
A is correct because the calculated side length is 25 cm, yielding a total perimeter of 100 cm.
The perpendicular bisecting property of diagonals is shared by squares and kites, and recognizing standard triplets like (7,24,25) saves critical time in competitive exams like RRBJE.