Based on the dimensions of the support for the slides, the missing length and slide length is 15 yards.
The number of 3-yard straight pieces needed is 15 straight pieces.
What number of straight pieces are needed?
The length of a single slide is the hypotenuse of the triangle which can be found using the Pythagoras theorem as:
Hypotenuse² = 9² + 12²
Hypotenuse = √(81 + 144)
= 15 yards
If a single slide is 15 yards, then 3 slides would be:
= 15 x 3
= 45 yards
The number of 3-yard straight pieces needed are:
= 45 / 3
= 15 pieces
Find out more on the Pythagoras theorem at https://brainly.com/question/343682
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