Real-Time Multi-Unit Geometry Engine

台形の面積計算ツール

無料の台形面積計算機で、台形の面積をすばやく正確に求めます。上底（a）、下底（b）、高さ（h）を入力してください。公式：面積 = (上底 + 下底) × 高さ ÷ 2。

Given Bases & Height (h) Given Bases & Slant Leg (c)

Presets:

Base a (Top Base) parallel base

Base b (Bottom Base) parallel base

Perpendicular Leg / Height (h) 90° vertical

CALCULATED TRAPEZOID AREA

Derived Slant Leg c = 5.657 cm • Perimeter = 0.257 m

Formula: A = ½(a + b)h Area = ½ × (6 + 10) × 4 = 8 × 4 = 32 cm²

Median (Midline) m = 8.00 cm

Equivalent: 0.0032 m² 0.0344 ft² 4.9600 in² 3200.00 mm²

Live Proportional Geometry Visualizer

4 Simple Steps

台形面積計算ツールの使い方

Follow this fast 4-step workflow to calculate any trapezoid or trapezium area instantly with live mathematical feedback.

Step 1 of 4

台形の上底（平行な辺a）の長さを入力します。

Input: a (Top Base) →

Step 2 of 4

台形の下底（平行な辺b）の長さを入力します。

Input: b (Bottom Base) →

Step 3 of 4

2つの平行な底辺間の垂直な高さ（h）を入力します。

Input: h (Perpendicular) →

Step 4 of 4

公式 A = ½ × (a + b) × h に基づき、瞬時に面積と計算過程を表示します。

Output: A = ½(a+b)h →

Standard Geometric Values

Reference measurements with step-by-step arithmetic. Click any row or use "Load" to test values instantly in the calculator above.

Base a	Base b	Height (h)	Calculated Area	Formula Step-by-Step
3 cm	5 cm	4 cm	16 cm²	½ × (3 + 5) × 4 = ½ × 8 × 4 = 16 cm²
6 cm	8 cm	5 cm	35 cm²	½ × (6 + 8) × 5 = ½ × 14 × 5 = 35 cm²
10 cm	14 cm	7 cm	84 cm²	½ × (10 + 14) × 7 = ½ × 24 × 7 = 84 cm²
2 cm	4 cm	3 cm	9 cm²	½ × (2 + 4) × 3 = ½ × 6 × 3 = 9 cm²
5 cm	9 cm	6 cm	42 cm²	½ × (5 + 9) × 6 = ½ × 14 × 6 = 42 cm²
7 cm	11 cm	8 cm	72 cm²	½ × (7 + 11) × 8 = ½ × 18 × 8 = 72 cm²
12 cm	16 cm	10 cm	140 cm²	½ × (12 + 16) × 10 = ½ × 28 × 10 = 140 cm²
1 cm	3 cm	2 cm	4 cm²	½ × (1 + 3) × 2 = ½ × 4 × 2 = 4 cm²
8 cm	12 cm	9 cm	90 cm²	½ × (8 + 12) × 9 = ½ × 20 × 9 = 90 cm²
15 cm	20 cm	12 cm	210 cm²	½ × (15 + 20) × 12 = ½ × 35 × 12 = 210 cm²