Question

Use Pythagoras theorem to check which of following triplets would make a right triangle.

• A. $5,20,25$
• B. $7,24,25$
• C. $7,23,25$
• D. $15,20,25$
  

Answer 1

Answer: (B), (D)

$7,24,25$
$15,20,25$

The pythagoras theorem is

$a^2=b^2+c^2$

${20}^2+5^2=425$ and ${25}^2=625$

so ${25}^2\ne {20}^2+5^2$

now check for b

${25}^2={24}^2+7^2$

$625=576+49$

$625=625$

so,${25}^2={24}^2+7^2$

now check for c

${25}^2={23}^2+7^2$

$625=529+49$

$625\ne 578$

Now ckeck for d

${25}^2={20}^2+{15}^2$

$625=400+225$

$625=625$

so only option $B$ and $D$ is correct.