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Number System
If \( 4^2 + 5^2 +x^2 = 21^2 \), then the value of x is
A) 9
B) 12
C) 15
D) 20
Correct Answer:
D) 20
Description for Correct answer:
Given \(4^2 + 5^2 + x^2 = 21^2 \)
It follows a pattern showing that the third number is multiple of first two numbers.
i.e 4 * 5 = 20 = x
\( 4^2 + 5^2 + 20 ^2 = 21^2\)
So x = 20
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