In a right- angled triangle, one side is 8.3cm and another is 7.7. How do you find the perimeter of the triangle?

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Answer 1 · 2018-03-26T08:37:12

Two cases:

$27.32 \ "cm"$

$19.1 \ "cm"$

I see two cases in the following problem.

CASE 1: FINDING THE HYPOTENUSE

Let's say that you need to find the hypotenuse $c$ , of the right-angled triangle.

Using Pythagoras' theorem, we got:

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

And so,

$8.3^2+7.7^2=c^2$

$c^2=128.18$

$c=sqrt(128.18)$

$=11.32$

Therefore, the perimeter will be $11.32+8.3+7.7=27.32$ centimeters.

CASE 2: FINDING THE OTHER LEG

If the hypotenuse is already given, in this case, $8.3 \ "cm"$ , we can easily find the other leg.

Using Pythagoras', $a^2+b^2=c^2$

$a^2=c^2-b^2$

Substitute in given values,

$a^2=8.3^2-7.7^2$

$=9.6$

$a=sqrt(9.6)$

$~~3.1$

And so, the perimeter here will be $3.1+8.3+7.7=19.1$ centimeters.