Question

evaluate after rationalizing the denominator of 25/✓40-✓80, it being given that root 5 is equals to 2.236 and root 10 is equals to 3.162

Answer 1

Hi ,

It is given that ,

√5 = 2.236 ,

√10 = 3.162 ,

Now ,

25/( √40 - √80 )

= 25/ [ ( √2×2×10 ) - √(4×4×5 ) ]

= 25 / [ 2√10 - 4√5 ]

= 25/[ 2 ( √10 - 2√5 ) ]

= [ 25( √10 + 2√5 )]/[2(√10 - 2√5)(√10 + 2√5 )]

= [ 25(√10 + 2√5 ) ]/[ 2( 10 - 20 ) ]

= [ 25 ( √10 + 2√5 ) ] /( - 20 )

= [ 25 ×5 ( √10 + 2√5 ) ]/ ( -20 × 5 )

= 125 ( √10 + 2√5 ) / ( -100 )

= 125 ( 3.162 + 2 × 2.236 ) / ( -100 )

= ( 125 × 7.634 )/( -100 )

= 954.25/( - 100 )

= - 9.5425

I hope this helps you.

: )