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How to do the fifth question on page 7 of the sixth grade math classroom exercise book? The surface area of the lower half cylinder is 6 cm in diameter and 4 cm in height.
It consists of a bottom (upper half, lower half, *** 1), a semi-cylindrical edge (curved surface) and a rectangle with a length of 6 and a width of 4. The area of the bottom is the square of 6/2 *3. 14, and the area of the bottom is 28.26cm2, so the rectangle with length of six and width of four is 6*4=24cm2.

The next step is to find the perimeter × height of the bottom, and then divide it by 2 to get 37.68cm2 of 6*3. 14*4/2.

37.68+24+28.26=89.94 (square centimeter) is here.

The comprehensive formula is (6 ÷ 2) 2× 3.14+4× 6+6× 3.14× 4 ÷ 2.

=9×3. 14+24+37.68

=28.26+24+37.68

=89.94 square centimeters

The area is 89.94 square centimeters.

The answer will be given by the part-time study Committee on behalf of class 6 math class for 6 years.