Trapezoidal area problem in unit 5 of grade 5 mathematics The shape of a fish pond is trapezoidal. Its upper bottom is 21 meters long and its lower bottom is 45 meters long. Its area is 759 square meters. How high is it?

This problem examines the calculation method of trapezoidal area
(1) Trapezoidal area formula: (upper bottom + lower bottom) × height △ 2
Let the height be X,
（21+45）×x÷2=759
66x÷2=759
33x=759
x=23
(2) If you haven't learned to solve equations, do so
Or according to the trapezoidal area formula: (upper bottom + lower bottom) × height △ 2
Height = 759 △ 2
=759÷33
=23
A: his height is 23 meters

A bus and a car run from 299 km apart at the same time. The bus runs 40 km per hour and the car 52 km per hour. A few hours later, the two cars are 69 km apart for the first time? In a few hours, the two cars are 69 kilometers apart for the second time?

(1) (299-69) / (40 + 52), = 230 △ 92, = 2.5 (hours); answer: after 2.5 hours, the two vehicles are 69 km apart for the first time. (2) 69 × 2 ^ (40 + 52), = 138 △ 92, = 1.5 (hours); answer: after 1.5 hours, the two vehicles are 69 km apart for the second time

A bus and a car run from 299 km apart at the same time. The bus runs 40 km per hour and the car 52 km per hour. A few hours later, the two cars are 69 km apart for the first time? In a few hours, the two cars are 69 kilometers apart for the second time?

Trapezoidal area problem in unit 5 of grade 5 mathematics The shape of a fish pond is trapezoidal. Its upper bottom is 21 meters long and its lower bottom is 45 meters long. Its area is 759 square meters. How high is it?