Find the difference 77/8-31/4

Find the area of a trapezoid with bases 14 cm and 18 cm and height 10 cm. 160 cm2 140 cm2 180 cm2 126 cm2

Mrs. avila is buying a wallpaper border to go on all of her kitchen walls. she wants to buy 5 extra feet of wallpaper border than she needs to be sure she has enough. she buys 55.5 feet of the border. the store owner selling the border uses the width of mrs. avila's kitchen to determine that the length of her kitchen must be 14.5 feet.

Could someone me with this question i’ve been stuck on it for 20 minutes