Given :
- A right angled triangle is given to us with two sides as √91 and √78 .
To Find :
- cosM as a fraction in simplest terms .
Solution :
We know that ,
→ cosM = base/hypotenuse .
By Pythagoras theorem ,
→ base ² + perpendicular ² = hypotenuse ²
→ (√78)² + (√91)² = hypotenuse ²
→ 78 + 91 = hypotenuse ²
→ 169 = hypotenuse ²
→ hypotenuse= 13
Therefore ,
→ cosM = MN/MO
→ cos M = √91/13
Hence the required answer is √91/13 .