Given expression = [(0.05)² + (0.41)² +(0.073)²] / [(0.005)² + (0.041)² + (0.0073)²]
Which is in form of [(a² + b² + c²)] /[ (a/10)² + (b/10)² + (c/10)²] = 100 x (a² + b² + c²) / (a²+b²+c²)

Correct Option: C

Given expression = [(0.05)² + (0.41)² +(0.073)²] / [(0.005)² + (0.041)² + (0.0073)²]
Which is in form of [(a² + b² + c²)] /[ (a/10)² + (b/10)² + (c/10)²] = 100 x (a² + b² + c²) / (a²+b²+c²)
= 100

a² - b² = (a + b) x (a - b)

Correct Option: A

Given expression =(13.065)²-(3.065)²
=(13.065 + 3.065) x (13.065 - 3.065)
=16.13 x 10
= 161.3

H.C.F. = (H.C.F. of Numerators) / ( L.C.M. of Denominators)

Correct Option: B

The given number are 0.54,1.80 and 7.20
So given number can be represented as fraction 54/100, 180/100 and 720/100
H.C.F. of 54, 180 and 720 is 18
∴ H.C.F. of given number= 18 / 100
= 0.18

Given expression = [(.356)² -2 x .356 x .106 + (.106)²] / [(.632)²+2 x .632 x .368 +(.368)²]
= (a² -2ab + b²) / (c²+2cd+d²)
= (a - b)² / (c + d)²

Correct Option: D

Given expression = [(.356)² -2 x .356 x .106 + (.106)²] / [(.632)²+2 x .632 x .368 +(.368)²]
= (a² -2ab + b²) / (c²+2cd+d²)
= (a - b)² / (c + d)²
= (.356 -.106)² / (.632 + .368)²
= (.25)²
= .0625

Given expression
=(3.65)²+(2.35)²-2 x 3.65 x 2.35 / 1.69

Correct Option: D

Given expression
=[(3.65)² + (2.35)² -2 x 3.65 x 2.35 ] / 1.69
=a² + b² - 2ab / 1.69, Where a = 3.65 and b = 2.35
=(a - b)² / 1.69
= (3.65 - 2.35)² / 1.69
= (1.3)² / 1.69
= 1.69 / 1.69
= 1