70.5k views
3 votes
The height of the sail on a boat is 7 feet less than 3 times the length of its base. If the

The area of the sail is 68 square feet, find its height and the length of the base.

User Mtay
by
4.5k points

1 Answer

1 vote

Answer:

Base=8 feet

Height=17 feet

Explanation:

Let

Base=x

Height=3x-7

Area=68 square feet

Area of the sail boat=1/2 * base * height

68 = 1/2 * x * (3x-7)

Cross product

68 * 2 =(1) * (x) * (3x-7)

136 = 3x^2 - 7x

3x^2 - 7x - 136=0

Using quadratic formula

x= -b +or- √b^2 - 4ac / 2a

= -(-7) +or- √(-7)^2 - (4)(3)(-136) / 2(3)

= 7 +or- √49 - (-1632) / 6

= 7 +or- √49+1632) / 6

= 7 +or- √1681 / 6

=7 +or- 41 /6

x= 7+41 / 6 or 7-41 / 6

=48/6 or -34/6

=8 or -17/3

Answer:

Explanation:

Let

Base=x

Height=3x-7

Area=68 square feet

Area of the sail boat=1/2 * base * height

68 = 1/2 * x * (3x-7)

Cross product

68 * 2 =(1) * (x) * (3x-7)

136 = 3x^2 - 7x

3x^2 - 7x - 136=0

Base of the boat can't be a negative value

Therefore,

Base = x = 8 feet

Height= 3x-7

=3(8)-7

=24-7

=17 feet

User Bjorn Thor Jonsson
by
4.6k points