the perimeter of rhombus is 100 cm and one of its shorter diagonal is 30 cm long find the length of other diagonal and area of Rhombus
Answers
Answer:
Let OPQRS be a rhombus
Given ,
Perimeter of the rhombus = 100 cm
Diagonal (d1) = 30cm
Other Diagonal (d2) = ?
Area of the rhombus = ?
Perimeter of the rhombus= 4×side of the rhombus
= 100 = 4s
= s = 25
Let d1 = Diagonal = QS = 30 cm
= QO = QS/2 = 30/2 = 15 cm ( Diagonal bisect each other at right angle )
Now , let us find the second diagonal of the rhombus
In right - angled triangle QOR using Pythagoras Theorem ,
QR² = QO² + OR²
= 25² = 15² + OR²
= OR² = 625 - 225 = 400
Therefore , OR = /400 = 20 cm
= PR = 2×OR = 2×20 = 40 cm (Diagonal bisect each other)
Let PR = d2 , Hence , area of a rhombus
= 1/2 × d1 × d2
= (1/2 × 30 × 40 ) cm²
= (1/2 × 1200) cm²
= 600 cm²
Hence , The area of the rhombus = 600 cm²