9514 1404 393
Answer:
A. 20 miles
Step-by-step explanation:
You will recognize this right triangle as a 3-4-5 right triangle scaled by a factor of 10 miles. That means the "old road" length is 50 miles. The new road lenth is 40+30 = 70 miles, so the added distance is ...
70 miles - 50 miles = 20 miles . . . . extra travel distance
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Maybe you've never heard of a 3-4-5 right triangle, so you need to use the Pythagorean theorem to compute the length of the old road. It tells you the square of that length is the sum of the squares of the new road segment:
OR² = 40² + 30²
OR² = 1600 +900 = 2500
OR = √2500 = 50 . . . . the length of the old road is 50 miles
