Question

v) If the length of diagonal of a rectangle is 10cm. and area is 62.5 sq. cm., then the sum
of their length and breadth is
(a) 12 cm. (b) 15 cm.
(c) 20 cm.
(d) 25 cm​

Answer 1

Answer:

if we consider one diagonl and other two sides of a rectangle joining the end poinst of that diagonal, the figure will be a aright angled triangle

so

diag² = length²+breadth²

100 = (l+b)²-2lb

100 = (l+b)²-2*62.5

(l+b)² = 225

l+b = 15

answer is b

Answer 2

Answer:

$d { }^{2} = l {}^{2} + b {}^{2} \\ 100 = (l + b) {}^{2} - 2lb \\ 100 = (l + b) {}^{2} - 2 \times 62.5 \\ (l + b) {}^{2} = 225 \\ l + b = 15$

Step-by-step explanation:

OPTION B IS CORRECT.

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