Question

The area of a trapezium is 330cm2 and the length of one of
the parallel sides is 14 cm. If its height is 15 cm find the length of
the other parallel side

Answer 1

Step-by-step explanation

area=330cm2  h=15cm  a=14 b=?

area of trapezium= 1/2h(a+b)

  330= 1/2 * 15 (14+b)

        =  7.5(14+b)

        = 105 + 7.5b

7.5b = 330-105

        = 225

b= 225/7.5

    30

   

Answer 2

${\large{\sf{\pmb{\underline{About \; question...}}}}}$

☀ Correct question : The area of a trapezium is 330cm² and the length of one of the parallel sides is 14 cm. If its height is 15 cm find the length of the other parallel side.

☀ Understanding the question : This question says that we have to find out the length of the other parallel side of a trapezium whose area is 330 cm², height is 15 cm and the length of one of the parallel sides is 14 cm. Let's do it..!

${\large{\sf{\pmb{\underline{Given \; that...}}}}}$

➟ Area of a trapezium = 330 cm²

➟ Height of a trapezium = 15 cm

➟ The length of one of the parallel side of that trapezium = 14 cm

${\large{\sf{\pmb{\underline{To \; find...}}}}}$

➟ The length of the other parallel side of that trapezium.

${\large{\sf{\pmb{\underline{Solution...}}}}}$

➟ The length of the other parallel side of that trapezium = 30 cm

${\large{\sf{\pmb{\underline{Using \; concepts...}}}}}$

➟ Formula to find area of a trapezium

${\large{\sf{\pmb{\underline{Using \; formulas...}}}}}$

➟ ${\small{\boxed{\sf{Area \: of \: trapezium \: = \dfrac{1}{2} \times (l_{1} + l_{2}) \times h}}}}$

${\large{\sf{\pmb{\underline{Full \; Solution...}}}}}$

➟ Area = 1/2 × (l₁+l₂) × h

➟ 330 = 1/2 × (l₁+l₂) × h

➟ 330 = 1/2 × (14+l₂) × 15

➟ 330 = 15/2 × (14+l₂)

➟ 330 = 7.5 × (14+l₂)

➟ 330 = 105 × 7.5l₂

➟ 330-105 = 7.5l₂

➟ 225 = 7.5l₂

➟ l₂ = 225/7.5

➟ l₂ = 30 cm

• Henceforth, 30 cm is the length of the other parallel side of that trapezium

${\large{\sf{\pmb{\underline{Verification...}}}}}$

➟ Area = 1/2 × (l₁+l₂) × h

➟ Area = 1/2 × (14+30) × 15

➟ Area = 1/2 × (44) × 15

➟ Area = 1 × 22 × 15

➟ Area = 1 × 330

➟ Area = 330 cm²