3. a) The missing length, obtained using the Pythagorean theorem is 10 meters
The steps used to find the missing length can be presented as follows;
3. a) The figure consists of a large triangle, composed of two right triangles. The length of a leg of the large right triangle can be found using the Pythagorean theorem as follows;
Length of the leg of the right triangle is; √(17² - 8²) = 15
The missing length is the hypotenuse side of the small right triangle
Leg lengths of the small right triangle are;
8 m and (21 - 15) = 6 m
Length of the hypotenuse side of the small right triangle is therefore;
Hypotenuse length is; √(8² + 6²) = 10
The missing length, which is the hypotenuse side of the small right triangle is 10 m