5 feet
Step-by-step explanation:
Well use the right-angled triangle formulae to find the unknown side;
a² + b² = (hypotenuse) c²
Therefore;
12² + x² = 13²
X² = 13² – 12²
x2 = 169 - 144
X² = 25
X = sqrt (25)
X = 5
Learn More:
For more on right -angled triangles check out;
https://brainly.com/question/12669361
https://brainly.com/question/12046883
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