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Big Ideas Math: Modeling Real Life, Grade 8

BI

Big Ideas Math: Modeling Real Life, Grade 8 View details

7. Perimeters and Areas of Similar Figures

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Exercise 5 Page 87

The area of a trapezoid is one half the product of the height and the sum of the bases.

35km^2

Practice makes perfect

The area of a trapezoid is one half the product of its height and the sum of its bases. In the given diagram, we can see that the lengths of the bases are 6 and 8 kilometers, and the height is 5 kilometers.

Having the height and the lengths of the bases, we can substitute them into the formula for the area of a trapezoid.

A=1/2h(b_1+b_2)

SubstituteValues

Substitute values

A=1/2( 5)( 8+ 6)

▼

Evaluate right-hand side

Add terms

A=1/2(5)(14)

Multiply

A=1/2(70)

MoveRightFacToNum

a/c* b = a* b/c

A = 70/2

Simplify quotient

A = 35

The area of the trapezoid is 35 kilometers.

Subchapter links

Try It p.84-85

Self-Assessment for Concepts & Skills p.85

Self-Assessment for Problem Solving p.86

Review & Refresh p.87

Concepts, Skills, & Problem Solving p.87-88