9514 1404 393
Answer:
12.5 cm
Step-by-step explanation:
Triangle IDA is a 3-4-5 right triangle with a scale factor of 5. That is, segment AI is 25 cm long. Since IS is half the length of the diagonal, it is ...
IS = (25 cm)/2
IS = 12.5 cm
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If you like, you can work out the length of AI using the Pythagorean theorem:
AI² = DI² +DA²
AI = √(15² +20²) = √(225 +400) = √625 = 25
