The length of one base of a trapezoid is 12 less than 3 times the length of the other base. If the trapezoid has a height of 10 feet and an area of 100 square feet, find the length of the shorter base.



Answer :

Certainly! Let's solve this step-by-step.

1. Define the variables:
Let [tex]\( x \)[/tex] be the length of the shorter base of the trapezoid.

2. Express the length of the longer base in terms of [tex]\( x \)[/tex]:
According to the problem, the length of the longer base is [tex]\( 3x - 12 \)[/tex].

3. Use the formula for the area of a trapezoid:
The area of a trapezoid is given by:
[tex]\[ \text{Area} = \frac{1}{2} \times (\text{Base 1} + \text{Base 2}) \times \text{Height} \][/tex]
For our trapezoid, this becomes:
[tex]\[ 100 = \frac{1}{2} \times (x + (3x - 12)) \times 10 \][/tex]

4. Simplify the equation:
Combine the bases:
[tex]\[ 100 = \frac{1}{2} \times (4x - 12) \times 10 \][/tex]
Multiply both sides by 2 to get rid of the fraction:
[tex]\[ 200 = (4x - 12) \times 10 \][/tex]
Divide both sides by 10:
[tex]\[ 20 = 4x - 12 \][/tex]

5. Solve for [tex]\( x \)[/tex]:
Add 12 to both sides:
[tex]\[ 32 = 4x \][/tex]
Divide both sides by 4:
[tex]\[ x = 8 \][/tex]

6. Conclusion:
The length of the shorter base is [tex]\( 8 \)[/tex] feet.