Answer:
see explanation
Step-by-step explanation:
Her error is in squaring (2y)²
She has (2y)² = 2y²
when it should be 2y × 2y = 4y²
Then
(2y)² = 6² + 8²
4y² = 36 + 64
4y² = 100 ( divide both sides by 4 )
y² = 25 ( take square root of both sides )
y =
= 5
Answer:
7.9
4.2
9.3
17.8
Step-by-step explanation:
8. √63
the square of 8 is 64 √63 is close to 64 so we can say it's 7.9 approximately
9. √18
the square of 4 is 16, √18 is greater than 16 so we can say it's 4.2 approximately
10. √87
the square of 9 is 81, √87 is greater than 81 so we can say the value of it is approximately 9.3
11. √319
the square of 18 is 324, √319 is smaller than 324 so we can say it's 17.8
40 mile radius covers 10 times more than 4 mile radius
They would have to work 15 hours and 50 minutes