A model boat is made to a scale of 1:20. This scale can be applied to any units, so 1mm measured on the model is 20mm on the actual boat, 1 cm measured on the model is 20cm on the actual boat. a) If the 1:20 model boat is 15cm wide, how wide is the actual boat? b) If the boat has a mast of height 4m, how high is the mast on the model?

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

other answer is correct. i had used the radius of the radius somehow. a website: