1. The circumference of a rectangle is 36 meters, and the length-width ratio is 5:4. The area of this rectangle is () square meters. You'd better show me the formula. )

The sum of length and width is

36 ÷ 2 = 18 (m)

Changshi

18 ÷ (5+4) × 5 = 10 (m)

Hiroshi Fujiwara (male name)

18 ÷ (5+4) × 4 = 8 (m)

The area is

10× 8 = 80 (m2)

The circumference of a right triangle is 48 cm, and the ratio of three sides is 3:4:5. Is the area of this triangle () or a column? Let me see.

The two right-angled sides are

48 ÷ (3+4+5) × 3 = 12 (cm)

48 ÷ (3+4+5) × 4 = 16 (cm)

The area is

12× 16÷ 2 = 96 (square centimeter)

Second, multiple choice questions.

1. If Party A and Party B complete the same project in a time ratio of 5:6, then their efficiency ratio is (④).

111:625:1135: 646: 5 (used to solve problems, do not understand)

The efficiency ratio is inversely proportional to the time ratio.

3. The ratio of the number of eggs laid by the big hen and the little hen is 10: 9. This big hen laid two more eggs than this little hen. Do you know how many eggs the big hen and the little hen have laid? (Application problems)

The big hen gave birth.

2 ÷ (10-9) × 10 = 20 (piece)

The little hen gave birth.

2 ÷ (10-9) × 9 = 18 (pieces)