Area Problems
One diagonal of a rhombus is 60% of the other diagonal. Then, area of the rhombus is how many times the square of the length of the larger diagonal?
Let one diagonal be k.Then, other diagonal = (60k/100) = 3k/5 cmArea of rhombus =(1/2) x k x (3k/5) = (3/10) = 3/10 (square of longer diagonal)Hence, area of rhombus is 3/10 times.
Let the side of the square(ABCD) be x metres. Then, AB + BC = 2x metres. AC = √2x = (1.41x) m. Saving on 2x metres = (0.59x) m. Saving % = ❨ 0.59x x 100 ❩% = 30%
Area of equilateral triangle = ?3a2/4 = x ......(i)And perimeter = 3a = y ? a = y/3 ....(ii)Now, Putting the value of a from Eq. (ii) in Eq. (i). we get?3 (y/3)2/4 = x ? x = ?3 x y2/36? x = y2/3?3x = y2/12?312?3 x = y2On squaring both sides, we get y4 = 432x2
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? cm2Required increase percent [1025/(4?)] x 2500/? x 100 = 41/4%= 10.25%
EXAMIANS