I need to find the volume of these but my teacher never went over trapezoidal prisms and I need help. I'm very sorry. Thank you!

42) A trapezoidal prism of height 12 cm. The parallel sides of the base have lengths 12 cm and 6 cm. The other sides of the base are each 6 cm. The trapezoid's altitude measures 5.2 cm.

45) A trapezoidal prism of height 6 yd. The parallel sides of the base have lengths 9 yd and 4 yd. The other sides of the base are each 5 yd. The trapezoid's altitude measures 4.3 yd

Guest Sep 5, 2018

#1**+1 **

42) A trapezoidal prism of height 12 cm. The parallel sides of the base have lengths 12 cm and 6 cm. The other sides of the base are each 6 cm. The trapezoid's altitude measures 5.2 cm.

The key here is to find the * area* of the trapezoidal base and then multiply this area by the

* Area* of the trapezoid = [ base area ] = (1/2) (altitude of the trapezoid) * (sum of the base lengths) =

(1/2) ( 5.2) (12 + 6) =

(1/2) (5.2) (18) =

9 * 5.2 =

46.8 cm

Now....the volume = base are * height of the prism = 46.8 * 12 = 561.6 cm^3

45) A trapezoidal prism of height 6 yd. The parallel sides of the base have lengths 9 yd and 4 yd. The other sides of the base are each 5 yd. The trapezoid's altitude measures 4.3 yd

This one is similar

Area of the trapezoid = (1/2) (4.3) (9 + 4) = (1/2) (4.3) (13) = 27.95 yd

Volume of the prism = 6 (27.95) = 167.7 yd^3

BTW...here's a website that might help : https://study.com/academy/answer/how-do-you-find-the-volume-of-trapezoidal-prism.html

CPhill Sep 5, 2018