Powers and Roots Practice Test 3

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Question : 25 of 40

Marks: +1, -0

If 3a = 4b = 6c and

a + b + c = 27√ 29

, then

√{a^2+b^2+c^2}

is:

89
87
81
$3√ 29$

Solution:

Here, 3a = 4b = 6c
∴ a = 2c and

b = 3/ 2 c

Now,

a + b + c = 27√ 29

⇒2c+3/2c+c=27√29

⇒c=6√29

Again,

a = 2c = 2 × 6√ 29= 12 √29

Now,

b=3/2c=9 √29

√{a^2+b^2+c^2}

=√{(12√29)^2+(9√29)^2+(6√29)^2}

=√{261×29}=√{9×29×29}

=3×29=87

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