Area of square = 64 sq cm
(Side)2 = 64
? Side = ?64 = 8 cm
According to the question,
? 2?r = 4 x 8
? r = (4 x 8)/2?
? r = 16/?
? Area of the circle
= ? x (16/?) x (16/?) sq cm
= 256/? sq cm.
Diameter of the circle = 13 + 5 = 18 cm
? Radius = Diameter/2 =18/2 = 9 cm
Area of the circle = ?r2 = (22/7) x 92
= (22 x 81)/9
= 1782/7
= 254.57 sq cm
= 255 sq cm
Let the sides of trapezium be 5k and 3k, respectively
According to the question,
(1/2) x [(5k + 3k) x 12] = 384
? 8k = (384 x 2)/12 = 64
? k = 64/8 = 8 cm
Length of smaller of the parallel sides = 8 x 3 = 24 cm
Original breadth of rectangle = 720/30 = 24 cm
Now , area of rectangle = (5/4) x 720 = 900 cm2
? New length of rectangle = 900/24 = 37.5 cm
? New perimeter of rectangle = 2(l+ b)
= 2(37.5 + 24 )
= 2 x 61.5
= 123 cm
Let the width of the rectangle = k units
? Length = (2k + 5) units.
According to the question,
Area = k(2k + 5)
? 75 = 2k2 + 5k
? 2k2 + 5k - 75 = 0
? 2k2 + 15k - 10k - 75 = 0
? k(2k + 15) - 5(2k + 15) = 0
? (2k + 15) (k - 5) = 0
? k = 5 and -15/2
Width cannot be negative.
? Width = 5 units
? Length = 2x + 5 = 2 x 5 + 5 = 15 unit
? perimeter of the rectangle = 2(15 + 5)
= 40 units
Let the length of rectangle = L m
? Breadth of rectangle = B m
Using conditions from the question,
L - B = 23 ....(i)
2(L + B) = 206
L + B = 103 ....(ii)
On adding Eqs. (i) and (ii), we get
2L = 126
? L = 63 m
? B = 103 - 63 = 40 m
Then , area of rectangle = L x B
= 63 x 40
= 2520 m2 .
Circumference of the circle = 2?r = 25
? r = 25 / (2?)
According to the formula,
Side of inscribed square = r?2
= 25 / (2?r x ?2)
= 25 / (??2 ) cm
? 1/2 x 2 ? x h
= ?3/4 x (2 ?3)2
? h = 3 cm.
Let circumference = 100 cm .
Then, ? 2?r = 100
? r = 100/2?
=50/?
? New circumference
= 105 cm
Then, 2?R = 105
? R = 105 / (2?)
&rArr Original area = [ ? x (50/?) x (50/?) ]
= 2500/? cm2
? New Area = [? x (105/2?) x (105/2?)]
= 11025 / (4?) cm2
? Increase in area = [11025/(4?)] - 2500/? cm2
= 1025 / 4? cm2
Required increase percent [1025/(4?)] x 2500/? x 100 = 41/4%
= 10.25%
Angle swept in 30 min= 180°
Area swept = [(22/7) x 7 x 7] x [180°/360°] cm2
= 77 cm2
? 22/7 x r2 = 462
? r2 = (462 x 7) /22 = 147
? r = 7?3 cm
? Height of the triangle = 3r = 21?3 cm
Now, ? a2 = a2/4 + (3r)2
? 3a2/4 = (21?3)2
? a2 = (1323 x 4)/3
? a = 21x 2 = 42 cm
? Perimeter = 3a = 3 x 42
=126 cm
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