Mathematics, 21.10.2020 16:01 KevinReed6444

Brainliest will be given to the correct answer! The formula for the area of a trapezoid is A = 1/2h (b1 + b2), where h is the height of the trapezoid, and b1 and b2 are the lengths of the bases.

Part A: Solve the formula for h. What is the height of a trapezoid that has an area of 91 cm2 and bases of 12 cm and 16 cm?

Part B: What method would you use to solve the formula for b1? What is the formula when solved for b1?

Part C: What is the length of the other base if one base of a trapezoid is 30 cm, the height of the trapezoid is 8.6 cm, and the area is 215 cm2?

Part D: If both bases of a trapezoid have the same length, can you find their lengths given the area and height of the trapezoid? Explain.

Answers: 3

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Answers

Answer from: giajramosp2r5da

A) The height of the trapezoid is 6.5 centimeters.

B) We used an algebraic approach to to solve the formula for $b_{1}$ . $b_{1} = \frac{2\cdot A}{h}-b_{2}$

C) The length of the other base of the trapezoid is 20 centimeters.

D) We can find their lengths as both have the same length and number of variable is reduced to one, from $b_{1}$ and $b_{2}$ to . $b = \frac{A}{h}$

Step-by-step explanation:

A) The formula for the area of a trapezoid is:

$A = \frac{1}{2}\cdot h \cdot (b_{1}+b_{2})$ (Eq. 1)

Where:

- Height of the trapezoid, measured in centimeters.

$b_{1}$ , $b_{2}$ - Lengths fo the bases, measured in centimeters.

- Area of the trapezoid, measured in square centimeters.

We proceed to clear the height of the trapezoid:

1) $A = \frac{1}{2} \cdot h \cdot (b_{1}+b_{2})$ Given.

2) $A = 2^{-1}\cdot h \cdot (b_{1}+b_{2})$ Definition of division.

3) $2\cdot A\cdot (b_{1}+b_{2})^{-1} = (2\cdot 2^{-1})\cdot h\cdot [(b_{1}+b_{2})\cdot (b_{1}+b_{2})^{-1}]$ Compatibility with multiplication/Commutative and associative properties.

4) $h = \frac{2\cdot A}{b_{1}+b_{2}}$ Existence of multiplicative inverse/Modulative property/Definition of division/Result

If we know that $A = 91\,cm^{2}$ , $b_{1} = 16\,cm$ and $b_{2} = 12\,cm$ , then height of the trapezoid is:

$h = \frac{2\cdot (91\,cm^{2})}{16\,cm+12\,cm}$

$h = 6.5\,cm$

The height of the trapezoid is 6.5 centimeters.

B) We should follow this procedure to solve the formula for $b_{1}$ :

1) $A = \frac{1}{2} \cdot h \cdot (b_{1}+b_{2})$ Given.

2) $A = 2^{-1}\cdot h \cdot (b_{1}+b_{2})$ Definition of division.

3) $2\cdot A \cdot h^{-1} = (2\cdot 2^{-1})\cdot (h\cdot h^{-1})\cdot (b_{1}+b_{2})$ Compatibility with multiplication/Commutative and associative properties.

4) $2\cdot A \cdot h^{-1} = b_{1}+b_{2}$ Existence of multiplicative inverse/Modulative property

5) $\frac{2\cdot A}{h} +(-b_{2}) = [b_{2}+(-b_{2})] +b_{1}$ Definition of division/Compatibility with addition/Commutative and associative properties

6) $b_{1} = \frac{2\cdot A}{h}-b_{2}$ Existence of additive inverse/Definition of subtraction/Modulative property/Result.

We used an algebraic approach to to solve the formula for $b_{1}$ .

C) We can use the result found in B) to determine the length of the remaining base of the trapezoid: ( $A= 215\,cm^{2}$ , $h = 8.6\,cm$ and $b_{2} = 30\,cm$ )

$b_{1} = \frac{2\cdot (215\,cm^{2})}{8.6\,cm} - 30\,cm$

$b_{1} = 20\,cm$

The length of the other base of the trapezoid is 20 centimeters.

D) Yes, we can find their lengths as both have the same length and number of variable is reduced to one, from $b_{1}$ and $b_{2}$ to . Now we present the procedure to clear below:

1) $A = \frac{1}{2} \cdot h \cdot (b_{1}+b_{2})$ Given.

2) $b_{1} = b_{2}$ Given.